Twin cities are a special case of two neighboring cities or urban centres that grow into a single conurbation – or narrowly separated urban areas – over time. There are no formal criteria, but twin cities are generally comparable in status and size, though not necessarily equal; a city and a substantially smaller suburb would not typically qualify, even if they were once separate. Tri-cities and quad cities are similar phenomena involving three or four municipalities.
A common – but not universal – scenario is two cities that developed concurrently on opposite sides of a river. For example, Minneapolis and Saint Paul in Minnesota – one of the most widely known pairs of "Twin Cities" – were founded several miles apart on opposite sides of the Mississippi River, and competed for prominence as they grew.
In some cases, twin cities are separated by a state border, such as Albury (New South Wales) and Wodonga (Victoria) in Australia, on opposite sides of the Murray River. Islamabad and Rawalpindi are the twin cities of Pakistan; Islamabad is the Federal Territory of Pakistan, while Rawalpindi is a city in the Punjab province. Cities on opposite sides of international borders sometimes share enough cultural and historical identity to be seen as twins, such as Haparanda (Sweden) and Tornio (Finland), Leticia (Colombia) and Tabatinga (Brazil), or Valga (Estonia) and Valka (Latvia).
In some cases twin cities eventually merge into a single legal municipality, such as Buda and Pest merging in 1873 into Budapest, Hungary; Brooklyn being annexed by New York City in 1898; or the three ancient cities of Hankou, Hanyang, and Wuchang joining in 1927 into Wuhan, China.
As a single urban area, twin cities may share an airport whose airport codes include both cities' initials, e.g., DFW (Dallas–Fort Worth), LBA (Leeds–Bradford), MSP (Minneapolis–Saint Paul), RDU (Raleigh and Durham), and CAK (Akron–Canton).
Examples
Africa
Egypt
Cairo and Giza. Triple cities if counting Shubra El Kheima.
Port Said and Port Fuad
Ghana
Sekondi-Takoradi
South Africa
Johannesburg and Pretoria, Gauteng Province
International
Democratic Republic of the Congo and Republic of the Congo border
Kinshasa, Democratic Republic of the Congo and Brazzaville, Republic of the Congo
Zimbabwe and Zambia border
Victoria Falls, Zimbabwe and Livingstone, Zambia
North America
Canada
Halifax and Dartmouth in Nova Scotia
Kitchener and Waterloo, Ontario
Battleford and North Battleford, Saskatchewan "The Battlefords"
Toronto and Mississauga
United States
Texarkana, Arkansas and Texarkana, Texas
Fort Collins and Loveland, Colorado
Hartford and New Britain, Connecticut
Fort Myers and Cape Coral, Florida
Fort Lauderdale and Miami, Florida
St. Petersburg and Tampa, Florida
Augusta, Georgia and North Augusta, South Carolina
Champaign and Urbana, Illinois
Bloomington and Normal, Illinois
Waterloo and Cedar Falls, Iowa
Bangor and Brewer, Maine
Lewiston and Auburn, Maine
Benton Harbor and St. Joseph, Michigan
Montague and Whitehall, Michigan
Houghton and Hancock, Michigan
Duluth, Minnesota, and Superior, Wisconsin
Minneapolis and Saint Paul, Minnesota
Natchez, Mississippi and Vidalia, Louisiana
Crystal City and Festus, Missouri
New York, New York and Jersey City, New Jersey
Raleigh and Durham, North Carolina
Winston-Salem and Greensboro, North Carolina (Winston-Salem itself was formerly a pair of twin cities, until the two merged)
Fargo, North Dakota, and Moorhead, Minnesota
Grand Forks, North Dakota and East Grand Forks, Minnesota
Cincinnati, Ohio and Covington, Kentucky
Portland, Oregon and Vancouver, Washington
Delmar, Maryland and Delmar, Delaware
Scranton and Wilkes-Barre, Pennsylvania
Allentown and Bethlehem, Pennsylvania
Greenville and Spartanburg, South Carolina
Bristol, Tennessee and Bristol, Virginia
Memphis, Tennessee and West Memphis, Arkansas
Dallas and Fort Worth, Texas
Midland and Odessa, Texas
Bluefield, Virginia and Bluefield, West Virginia
Neenah and Menasha, Wisconsin
Marinette, Wisconsin, and Menominee, Michigan
Seattle and Tacoma, Washington
Kansas City, Missouri and Kansas City, Kansas
International
Examples, sharing names or similar names, across an international border include:
Canada–United States border
Niagara Falls, Ontario, Canada; Niagara Falls, New York, United States
Sault Ste. Marie, Ontario, Canada; Sault Ste. Marie, Michigan, United States
North Portal, Saskatchewan, Canada; Portal, North Dakota, United States
Mexico–United States border
Tecate, Baja California, Mexico; Tecate, California, United States
Boquillas del Carmen, Coahuila, Mexico; Boquillas, Texas, United States
Naco, Sonora, Mexico; Naco, Arizona, United States
Nogales, Sonora, Mexico; Nogales, Arizona, United States
San Luis Río Colorado, Sonora, Mexico; San Luis, Arizona, United States
Nuevo Laredo, Tamaulipas, Mexico; Laredo, Texas, United States
Nuevo Progreso, Río Bravo, Tamaulipas, Mexico; Progreso, Texas, United States
Calexico, California, United States; Mexicali, Baja California, Mexico; see Calexico–Mexicali
Pairs with unrelated names:
Mexico–Guatemala border
Ciudad Hidalgo, Chiapas, Mexico and Ayutla, San Marcos, Guatemala
United States–Canada border
Detroit, Michigan, United States and Windsor, Ontario, Canada; see Detroit–Windsor
International Falls, Minnesota, United States and Fort Frances, Ontario, Canada
United States–Mexico border
Douglas, Arizona, United States and Agua Prieta, Sonora, Mexico
Yuma, Arizona, United States and San Luis Río Colorado, Sonora, Mexico
San Diego, California, United States and Tijuana, Baja California, Mexico; see San Diego–Tijuana
Brownsville, Texas, United States and Matamoros, Tamaulipas, Mexico; see Brownsville–Matamoros
Del Rio, Texas, United States and Ciudad Acuña, Coahuila, Mexico
Eagle Pass, Texas, United States and Piedras Negras, Coahuila, Mexico
El Paso, Texas, United States and Ciudad Juárez, Chihuahua, Mexico; see El Paso–Juárez
Presidio, Texas, United States and Manuel Ojinaga, Chihuahua, Mexico
Historic
Lloydminster, Alberta/Saskatchewan, Canada
Thunder Bay, Ontario, Canada
Saginaw and East Saginaw, Michigan, United States
Stanwood and East Stanwood, Washington, United States
Brooklyn and New York City, New York, United States
South America
Argentina
Carmen de Patagones and Viedma
Paraná, Entre Ríos and Santa Fe
Brazil
Americana, São Paulo and Santa Bárbara d'Oeste
Juazeiro and Petrolina
Olinda and Recife
Vila Velha and Vitória
Chile
Concepción and Talcahuano
Coquimbo and La Serena
Valparaiso and Viña del Mar
Peru
Callao and Lima
Venezuela
Acarigua and Araure
Guarenas and Guatire
International
Brazil-Paraguay border
Ponta Porã, Mato Grosso do Sul, Brazil ; Pedro Juan Caballero, Amambay, Paraguay
Brazil-Uruguay border
Sant'Ana do Livramento, Rio Grande do Sul, Brazil ; Rivera, Uruguay
Asia
Current
Bangladesh
Dhaka and Narayanganj, Bangladesh
China
Guangzhou and Foshan, China
Xi'an and Xianyang, China
Beijing and Langfang, China
Wuxi and Suzhou, China
Chaozhou and Shantou, China
Haifeng and Lufeng, China
Hong Kong and Shenzhen, China
India
Ahmedabad and Gandhinagar, India
Allahabad and Naini, India
Aurangabad and Jalna, India
Bangalore and Hosur, India
Bishangarh and Jalore, India
Chümoukedima and Dimapur, India
Cuttack and Bhubaneswar, India
Durg and Bhilai, India
Hubli and Dharwad, India
Mysore and Srirangapatna, Karnataka, India
Kankroli and Rajsamand, India
Kochi and Ernakulam, India
Coimbatore and Tiruppur
Kolkata and Howrah, India
Mumbai and Navi Mumbai, Maharashtra, India
Mumbai and Thane, Maharashtra, India
Munger and Jamalpur, India
Noida and Greater Noida, India
Pondicherry and Cuddalore, India
Pune and Pimpri-Chinchwad, Maharashtra, India
Ranchi and Hatia, India
Sangli and Miraj, Maharashtra, India
Surat and Navsari, India
Sumerpur and Sheoganj, India
Thrissur and Guruvayur, India
Vijayawada and Guntur, Andhra Pradesh, India
Bangarpet and Kolar Gold Fields, Karnataka, India
Harihar and Davangere, Karnataka, India
Shivamoga and Bhadravati, Karnataka, India
Arcot and Ranipet, Tamil Nadu, India
Attur and Narasingapuram, Tamil Nadu, India
Bhavani and Komarapalayam, Tamil Nadu, India
Dharmapuri and Nallampalli, Tamil Nadu, India
Erode and Pallipalayam, Tamil Nadu, India
Namakkal and Karur, Tamil Nadu, India
Tiruchirappalli and Srirangam, Tamil Nadu, India
Tirunelveli and Palayamkottai, Tamil Nadu, India
Hyderabad and Secunderabad, Telangana state, India
Asansol and Durgapur, West Bengal, India
Barrackpore and Barasat, West Bengal, India
Coochbehar and Alipurduar, West Bengal, India
Jalpaiguri and Mainaguri, West Bengal, India
Siliguri and Jalpaiguri, West Bengal, India
Vellore,Tamil Nadu,India and Chittoor, Andhra Pradesh, India
Chennai and Tambaram, Tamil Nadu, India
Iraq
Erbil and Mosul, Iraq
Seleucia and Ctesiphon, Iraq
Israel
Ramla and Lod, Israel
Tel Aviv and Jaffa, Israel
Japan
Aomori and Hakodate, Japan
Kamisu and Kashima, Japan
Kitakyushu and Shimonoseki, Japan
Kyoto and Otsu, Japan
Maebashi and Takasaki, Japan
Nasushiobara and Otawara, Japan
Okayama and Kurashiki, Japan
Osaka and Sakai, Japan
Sanjo and Tsubame, Japan
Toyohashi and Toyokawa, Japan
Tsukuba and Tsuchiura, Japan
Yokkaichi and Suzuka, Japan
Lebanon
Beirut and Jounieh, Lebanon
Nepal
Bharatpur and Gaindakot, Nepal
Butwal and Tilottama, Nepal
Nepalgunj and Kohalpur, Nepal
North Korea
Rason and Chongjin
Pakistan
Jhelum and Sarai Alamgir, Pakistan
Peshawar and Mardan, Pakistan
Rawalpindi and Islamabad, Pakistan
Palestine
Ramallah and al-Bireh, Palestine
Philippines
Baguio and La Trinidad, Philippines
Bantay and Vigan, Philippines
Bayombong and Solano, Philippines
Dagupan and Lingayen, Philippines
Daraga and Legazpi, Philippines
Dipolog and Dapitan, Philippines
Laoag and San Nicolas, Philippines
Lemery and Taal, Philippines
Palo and Tacloban, Philippines
Santo Tomas and Batangas, Philippines
Saudi Arabia
Dammam and Khobar, Saudi Arabia
South Korea
Seoul and Incheon, South Korea
Busan and Ulsan, South Korea
Sejong City and Daejeon, South Korea
Yangyang and Sokcho, South Korea
Taiwan
Taipei and New Taipei, Taiwan
Thailand
Bangkok and Nonthaburi, Thailand
Chiang Mai and Lamphun, Thailand
Songkhla and Hatyai, Thailand
Vietnam
Ho Chi Minh City and Binh Duong, Vietnam
Phan Rang-Tháp Chàm, Vietnam
International
Azerbaijan-Iran Border
Astara, Azerbaijan and Astara, Iran
China-North Korea Border
Dandong, China and Sinuiju, North Korea
China-Russia Border
Manzhouli, China and Zabaykalsk, Russia
Heihe, China and Blagoveshchensk, Russia
China-Vietnam Border
Dongxing, China and Mong Cai, Vietnam
Hekou, China and Lao Cai, Vietnam
Malaysia-Singapore Border
Johor Bahru, Malaysia and Singapore
Laos-Thailand Border
Vientiane, Laos and Nong Khai, Thailand Laos-Vietnam Border
Dansavan, Laos and Lao Bao, Vietnam
United Arab Emirates-Oman Border
Al Ain, United Arab Emirates and Al Buraimi, Oman
Historic
Victoria and Kowloon, colonial Hong Kong—although, in both colonial Hong Kong and the Hong Kong Special Administrative Region, Victoria is the only city recognised by law; they were widely considered to be separate cities until at least the mid-1970s
Chirala-Perala, India
Fukuoka (merger of east side of Naka river, Hakata, and the west side, Fukuoka)
Ise, Japan (merger of Uji, Yamada)
Joetsu, Japan (merger of Takada, Naoetsu)
Naha and Shuri, Okinawa, Japan, once separate cities, Shuri became integrated as a district of Naha
Wuhan, China (merger of Wuchang, Hankou, Hanyang)
Saigon and Cholon, Vietnam, merged into Saigon-Cholon, now Ho Chi Minh City.
Europe
Current
Denmark
Nørresundby and Aalborg, Denmark
Finland
Kotka and Hamina, Finland
France
Frejus and Saint-Raphaël, France
Lyon and Villeurbanne, France
Germany
Frankfurt and Offenbach, Germany
Ludwigshafen and Mannheim, Germany
Mainz and Wiesbaden, Germany
Mönchengladbach and Rheydt, Germany
Nuremberg and Fuerth, Germany
Sindelfingen and Böblingen, Germany
Ulm and Neu-Ulm, Germany
Villingen-Schwenningen, Germany
Ireland
Ballybofey and Stranorlar, in County Donegal, Ireland are often called the Twin Towns and form the built up area of Ballybofey and Stranorlar
Norway
Fredrikstad and Sarpsborg, Norway
Porsgrunn and Skien, Norway
Sandnes and Stavanger, Norway
Poland
Bydgoszcz and Toruń, Poland
Kalisz and Ostrów Wielkopolski, Poland
Portugal
Porto and Vila Nova de Gaia, Portugal
Póvoa de Varzim and Vila do Conde, Portugal
Serbia
Novi Sad and Petrovaradin, Serbia
Temerin and Bački Jarak, Serbia
Zemun and New Belgrade, Serbia
Spain
Alcobendas and San Sebastián de los Reyes, Spain
Aldaia and Alaquàs, Spain
Coslada and San Fernando de Henares, Spain
Elda and Petrer, Spain
Llombai and Catadau, Spain
Santa Cruz de Tenerife and San Cristóbal de la Laguna, Spain
Sweden
Jönköping and Huskvarna, Sweden
Ukraine
Donetsk and Makiivka, Ukraine
United Kingdom
Bournemouth and Poole, United Kingdom
Brighton and Hove, United Kingdom
Chatham and Rochester, United Kingdom
Chester, England and Saltney, Wales
Leeds and Bradford, United Kingdom
Manchester and Salford, United Kingdom
Newcastle upon Tyne and Gateshead, England
Liverpool and Birkenhead, England
Kingston upon Hull and Grimsby, England
Warwick and Leamington Spa, England
International
Austria–Slovakia border
Vienna, Austria and Bratislava, Slovakia. This is an example of capital cities of neighboring nations being twin cities of one another.
Austria–Slovenia border
Bad Radkersburg, Austria and Gornja Radgona, Slovenia
Belgium–France border
Comines, Belgium and Comines, France
Mouscron, Belgium and Tourcoing, France
Wervik, Belgium and Wervicq-Sud, France
Croatia–Bosnia and Herzegovina border
Slavonski Brod, Croatia and Bosanski Brod, Bosnia and Herzegovina
Czech Republic–Poland border
Český Těšín, Czech Republic and Cieszyn, Poland
Denmark–Sweden border
Copenhagen, Denmark and Malmö, Sweden
Estonia–Latvia border
Valga, Estonia and Valka, Latvia
Estonia–Russia border
Narva, Estonia and Ivangorod, Russia
Finland–Russia border
Imatra, Finland and Svetogorsk, Russia
Finland–Sweden border
Tornio, Finland and Haparanda, Sweden
France–Germany border
Strasbourg, France and Kehl, Germany
France–Spain border
Hendaye, France and Irun, Spain
Germany–Poland border
Frankfurt (Oder), Germany and Słubice, Poland
Görlitz, Germany and Zgorzelec, Poland
Guben, Germany and Gubin, Poland
Heringsdorf, Germany and Świnoujście, Poland
Germany–Switzerland border
Konstanz, Germany and Kreuzlingen, Switzerland
Laufenburg (Baden), Germany and Laufenburg, Aargau, Switzerland, separated between the Rhine River (used to be one city until 1801/1802).
Hungary–Slovakia border
Esztergom, Hungary and Štúrovo, Slovakia
Komárno, Slovakia and Komárom, Hungary
Ireland–United Kingdom border
Strabane, Northern Ireland and Lifford, Ireland
Italy–Slovenia border
Gorizia, Italy and Nova Gorica, Slovenia
Italy-Vatican City border
Rome, Italy and Vatican City, Holy See. Vatican City is the only sovereign state surrounded entirely by a single city, Rome. The Vatican was an area in Rome and part of Italy until 1929, when Pope Pius XI and Benito Mussolini signed the Lateran Treaty.
The Netherlands–Germany border
Kerkrade, The Netherlands and Herzogenrath, Germany
Spain–Gibraltar border
La Línea de la Concepción, Spain and Gibraltar
Switzerland–Germany-France border
Basel, Switzerland and Weil am Rhein, Germany and Saint Louis, France
Historic
Knokke and Heist-aan-Zee. United into Knokke-Heist, Belgium.
Gradec and Kaptol. United into Zagreb, Croatia.
Frýdek and Místek. United into Frýdek-Místek, Czech Republic.
Barmen and Elberfeld, Germany. United into Wuppertal.
Kouvola and Kuusankoski. United into Kouvola, Finland.
West Berlin, West Germany and East Berlin, East Germany. United into Berlin, Germany.
Buda and Pest. United into Budapest, Hungary.
Bielsko and Biała, Poland. United into Bielsko-Biała.
City of London and City of Westminster, England. Absorbed into London, United Kingdom.
Berwick-upon-Tweed and Tweedmouth, until the former was taken by England from Scotland.
Äänekoski and Suolahti. United into Äänekoski, Finland.
Oceania
Albury and Wodonga, Australia
Canberra and Queanbeyan, Australia
Darwin and Palmerston, Australia
Forster and Tuncurry, Australia
Gold Coast and Tweed Heads, Australia
Harden and Murrumburrah, Australia
Kalgoorlie and Boulder, Australia
Napier and Hastings, New Zealand
Perth and Fremantle, Australia
Townsville and Thuringowa, Australia
Tri-cities
Australia
Brisbane; Gold Coast; and Sunshine Coast, Queensland, Australia — see South East Queensland
Sydney; Wollongong; and Newcastle, Australia in the geological region known as the Sydney Basin
Canada
The Tri-cities of British Columbia consist of Coquitlam, Port Coquitlam, and Port Moody
The Tri-citites of Kitchener; Waterloo; and Cambridge, Ontario, Canada, the cities' collective metropolitan area is often called the K-W Tri-City Area
Tri-Town, Ontario, Canada - Cobalt, Haileybury and New Liskeard
China
Xiamen, Quanzhou, Zhangzhou, Fujian
Germany
Wuppertal, Remscheid, Solingen, Rhineland, originally a quad-city until 1929, when Elberfeld and Barmen merged to form Wuppertal
India
Chandigarh; Mohali; and Panchkula, India
Vijayawada; Amaravati; and Guntur, India
Chennai,Avadi and Tambaram
Warangal; Hanamkonda; Kazipet in India — see Warangal Tri-City
Japan
Kyoto; Osaka; Kobe - see Keihanshin
Malaysia
Parit Buntar, Perak; Nibong Tebal, Penang; and Bandar Baharu, Kedah
Tricity, Nepal, consisting of the cities of Baglung, Beni and Kushma
Philippines
Bacolod; Silay; Talisay, Philippines
Cebu City; Mandaue; and Lapu-Lapu City, Philippines
Angeles City; Mabalacat; and San Fernando, Philippines
Poland
Gdańsk; Gdynia; and Sopot, Poland — see Tricity, Poland
Wejherowo; Rumia; and Reda, Poland — see Kashubian Tricity
Saudi Arabia
The Dammam metropolitan area, consisting of Dammam; Dhahran; and Khobar, Saudi Arabia
South Africa
The metropolitan municipalities of Johannesburg, Tshwane (Pretoria) and Ekurhuleni (East Rand), Gauteng Province
Gqeberha (Port Elizabeth), Kariega (Uitenhage) and Despatch in Nelson Mandela Bay Metropolitan Municipality, Eastern Cape Province
East London, Bhisho and Qonce (King William's Town) in Buffalo City Metropolitan Municipality, Eastern Cape Province
Sudan
Khartoum; North Khartoum; and Omdurman, Sudan
Sweden
Stockholm; Solna; and Sundbyberg, Sweden
Trollhättan; Uddevalla; and Vänersborg, Sweden
United Arab Emirates
The Dubai-Sharjah-Ajman metropolitan area, consisting of Dubai; Sharjah; and Ajman, United Arab Emirates
United States
Burbank; Glendale; and Pasadena, in Los Angeles County, California, United States
Fremont; Newark; and Union City, in Alameda County, California, United States
Oceanside; Vista; and Carlsbad, in San Diego County, California, United States
Riverside; San Bernardino; and Ontario, California, United States, the cities' collective metropolitan area is often called the Inland Empire
San Jose; San Francisco; and Oakland, California, United States
College Park; East Point; and Hapeville, Georgia, United States, all of which are near Hartsfield–Jackson Atlanta International Airport
Geneva; Batavia; and St. Charles, in Kane County, Illinois, United States, also known as Tri-Cities, Illinois
Bay City; Saginaw; and Midland, Michigan, United States, the cities' collective metropolitan area is often called the Greater Tri Cities, the Great Lakes Bay Region or the MBS region
Ferrysburg; Grand Haven; and Spring Lake, Michigan, United States
Iron River, Caspian, and Gaastra, Michigan, United States
Ironwood; Bessemer; and Wakefield, Michigan, United States
Grand Island; Kearney; and Hastings, in south-central Nebraska, United States, also known as Tri-Cities, Nebraska
Rochester; Dover; and Somersworth, New Hampshire, United States
Farmington; Bloomfield; and Aztec, New Mexico, United States
Albany, Troy, and Schenectady, New York, United States, in the region known as the Capital District
Binghamton; Endicott; and Johnson City, New York, United States, the cities' collective metropolitan area is often called the Triple Cities
New York, New York; Newark; and Jersey City, New Jersey, United States
Greensboro; Winston-Salem; and High Point, North Carolina, United States, the cities' collective metropolitan area is often called the Piedmont Triad
Raleigh; Durham; and Chapel Hill, North Carolina, United States, the cities' collective metropolitan area is often called the Research Triangle
Tuttle; Newcastle; and Blanchard, Oklahoma, United States, also known as the Tri-City Area
Johnson City; Kingsport; and Bristol, Tennessee/Bristol, Virginia, United States, also known as Tri-Cities, Tennessee
Beaumont; Port Arthur; and Orange, Texas, United States, also known as the Golden Triangle (Texas)
Dallas; Fort Worth; and Arlington, Texas, United States
Petersburg; Colonial Heights; and Hopewell, Virginia, United States, also known as Tri-Cities, Virginia
Pasco; Richland; and Kennewick, Washington, United States, also known as Tri-Cities, Washington
Washington, D.C., Alexandria, Virginia, and Arlington County, Virginia, United States
Quad cities
China
Xinhui, Taishan, Kaiping, and Enping together formed Siyi area in Jiangmen, Guangdong
Finland
Helsinki, Espoo, Kauniainen and Vantaa in Uusimaa, Finland; together form the largest metropolis in the country and its actual capital area.
Thailand
Pattaya-Chonburi Metropolitan Area consists of the City of Pattaya, Town of Chonburi, Portal town of Laem Chabang and Town of Sattahip on the west coast of Chonburi Province, Thailand
United Kingdom
The West Yorkshire Built-up Area consists of the cities of Leeds, Bradford and Wakefield, and the large town of Huddersfield, United Kingdom.
United States
The Florence-Muscle Shoals Metropolitan Area in Alabama, United States, is locally referred to as "the Quad Cities", with Florence, Muscle Shoals, Sheffield, and Tuscumbia, Alabama. Formerly, when Muscle Shoals was a mere village, this region was known as "Tri-Cities", Alabama. In fact, all except Florence are incorporated as towns.
Quad Cities of Davenport and Bettendorf, Iowa, and Rock Island and Moline, Illinois, United States. It also includes a fifth member, East Moline, Illinois.
Allentown/Bethlehem, Pennsylvania and Easton, Pennsylvania/Phillipsburg, New Jersey, United States; the collective area is often called the Lehigh Valley
The Quad Cities of Minnesota, United States, consist of Virginia, Eveleth, Gilbert, and Mountain Iron.
The cities of Pullman, Washington, Moscow, Idaho, Lewiston, Idaho and Clarkston, Washington, United States, have marketed themselves as "Quad Cities."
More than four cities
Denmark
The Triangle Region (Denmark), consisting of Billund, Fredericia, Haderslev, Kolding, Middelfart, Vejen and Vejle, Denmark.
Germany
The Ruhr district (Germany): consisting of Dortmund, Essen, Duisburg, Bochum, Oberhausen, Mülheim, Bottrop, Gelsenkirchen and Herne in its core.
India
In India: the cities of New Delhi, Noida, Greater Noida, Ghaziabad, Gurgaon and Faridabad have formed a huge metropolitan area known as National Capital Region (India).
Malaysia
In Malaysia: the cities of Kuala Lumpur, Petaling Jaya, Subang Jaya, Puchong, Shah Alam, Klang, Port Klang, Putrajaya, Cyberjaya, and Kajang have formed a huge metropolitan area (around the size of Singapore) known as Greater Kuala Lumpur.
Kazakhstan
In Kazakhstan: the cities of Karaganda, Temirtau, Shakhtinsk, Abai, Saran, Topar, Dolinka, Shahan, Kokpekti, and Novodolinsky form an industrial-mining area known since Soviet times as Karbass (Karaganda coal basin).
United States
In the US states of Illinois and Iowa: The cities of Davenport and Bettendorf in Iowa; Rock Island, Moline and East Moline in Illinois form a metropolitan area known as the Quad Cities.
In the US states of Michigan and Wisconsin sit the 6 cities of Iron Mountain, Kingsford, Quinnesec, Norway (in Michigan), Aurora, and Niagara (in Wisconsin). The area is collectively known as the Iron Mountain Area.
In the US state of Virginia: Norfolk, Chesapeake, Hampton, Newport News, Portsmouth, Suffolk, and Virginia Beach; the cities' collective metropolitan area is often called Hampton Roads
Examples of cities formed by amalgamation
Asia
China
Wuhan in China consists of the towns of Wuchang, Hankou, and Hanyang in Hubei Province.
India
Delhi, India: What used to be Old Delhi, New Delhi, and a collection of smaller villages has now grown into the current megalopolis that is seen today, also known as the National Capital Region (NCR)
In Telangana, India, the cities of Hyderabad and Secunderabad are merged to form Greater Hyderabad.
Japan
Fukuoka in Japan, a city of 1.4 million people, formerly the twin cities of Hakata and Fukuoka until the late 19th century.
Kitakyushu in Japan, a city of 900,000 people, created in 1963 by the merger of Yahata, Kokura, Moji, Wakamatsu, and Tobata. Yahata and Kokura had formerly been major cities in their own right.
Saitama in Japan, a city of 1.2 million people, created in 2001 by the merger of the cities of Urawa, Omiya, Yono, and later Iwatsuki. Urawa and Omiya could formerly have been considered twin cities.
Pakistan
Islamabad, the capital city of Pakistan, has been expanded to include smaller towns including Rawat in its territory.
Lahore, the second largest city of Pakistan, has, as of 2013, grown out so much that small towns by this giant city, such as Shahdara, have been absorbed in its city limits.
Taiwan
The former cities of Taoyuan and Zhongli, Taiwan, which merged along with the entire county in 2014 to form a single municipality city of Taoyuan, the two cities sit directly next to each other and shares almost the same population.
Thailand
Bangkok, the capital and largest city of Thailand, was created in 1971, when the previous Bangkok province (Phra Nakhon) was merged with Thonburi province.
Vietnam
The cities of Saigon and Cholon merged in 1931 to form a single city named Saigon-Cholon; in 1956, the name Cholon was dropped and the city became known as Saigon (now Ho Chi Minh City), Vietnam.
Europe
Germany
Berlin (Berlin and Cölln), in Germany
Duisburg (Duisburg and Hamborn, 1929–1935 called Duisburg-Hamborn), in North Rhine-Westphalia, Germany
Wuppertal (Barmen and Elberfeld), in North Rhine-Westphalia, Germany
Greece
Athens incorporated dozens of villages and towns and absorbed whole of Athens basin and parts outside of it, notably Piraeus.
Hungary
Budapest, Hungary is the amalgamation of Buda, Pest and Óbuda.
The Netherlands
Eindhoven, the Netherlands, merged with five neighbouring municipalities (Woensel, Tongelre, Stratum, Gestel en Blaarthem and Strijp) into the new Groot-Eindhoven ("Greater Eindhoven") in 1920. The prefix "Groot-" was later dropped.
Spain
Madrid, Spain, evolved by absorption of other towns (like Tetuán de las Victorias, Vallecas, Chamartín de la Rosa or Aravaca)
United Kingdom
Edinburgh, Scotland, absorbed a number of surrounding villages, but most notably the separate burgh of Leith.
London, England, grew from its cores in the City of London and the City of Westminster to encompass many other towns and villages within neighbouring counties and absorbed almost the whole of Middlesex county.
Manchester and the city of Salford, England in the Metropolitan County of Greater Manchester (formerly in Lancashire).
Stoke-on-Trent, England was created in 1910 from the towns of Burslem, Hanley, Tunstall, Longton, Fenton and Stoke, taking its name from the latter. Neighbouring Newcastle-under-Lyme remains a separate town.
North America
Canada
Port Alberni, British Columbia, Canada, was formed in 1967 when Alberni and Port Alberni, merged to become one city.
Winnipeg, Manitoba, Canada, amalgamated with 12 surrounding municipalities and its metropolitan corporation in 1971 under what was referred to as unicity reforms in local government restructuring.
Halifax and Dartmouth, Nova Scotia, Canada, were merged in 1996 along with Bedford and Halifax County to create the Halifax Regional Municipality.
Greater Sudbury, Ontario, Canada, was formed in 2001 by the amalgamation of the former Regional Municipality of Sudbury, comprising the municipalities of Sudbury, Nickel Centre, Valley East, Capreol, Rayside-Balfour, Onaping Falls and Walden, plus a number of previously unamalgamated townships. The amalgamation made it the most populous city in the Northern Ontario region.
Kingston, Ontario, Canada, was amalgamated in 1998 with the neighboring Kingston and Pittsburgh Townships.
Ottawa, Ontario, Canada, was given its large area by the amalgamation in 2001 of the old City of Ottawa, the suburbs of Nepean, Kanata, Gloucester, Rockcliffe Park, Vanier and Cumberland, Orleans, and the rural townships of West Carleton, Osgoode, Rideau, and Goulbourn
Toronto, Ontario, Canada, formed by an amalgamation of the Old Toronto with East York, Etobicoke, North York, Scarborough and York, which were themselves products of earlier amalgamations.
Thunder Bay, Ontario, Canada (Fort William and Port Arthur).
Gatineau, Quebec, Canada, formed by the amalgamation of the old City of Gatineau, City of Hull, City of Aylmer, City of Buckingham and the Municipality of Masson-Angers all facing the City of Ottawa, Ontario from the north shore of the Ottawa River.
Montreal, Quebec, Canada, was merged with the other 27 communities on the Island of Montreal by an act in the Quebec Parliament in 2002. Following a change in the provincial government, several communities later voted via referendum to de-merge and there are now a total of 15, leaving Montreal merged with the other 12.
Saguenay, Quebec, Canada (Chicoutimi, Jonquière, et al.)
Lloydminster, Canada, on the Saskatchewan-Alberta border, was formed as a single entity in 1903, when both future provinces were part of the Northwest Territories, but was divided into two separate entities in 1905 because the border between the newly created provinces bisected the community. In 1930, the two towns were reunited as a single town under the shared jurisdiction of both provinces, and Lloydminster was reincorporated as a single city in 1958.
United States
Helena–West Helena, Arkansas was formed in 2006 by the merger of the previous cities of Helena and West Helena.
Fremont, California was formed in 1956 by the combination of the five towns of Centerville, Irvington, Niles, Mission San Jose, and Warm Springs, California. The town of Newark has always refused to merge into Fremont, and Newark is completely surrounded by Fremont.
Boston, Massachusetts is made up of the former towns of Boston, Dorchester, Brighton, Roxbury, Charlestown, and Hyde Park.
Iron River, Michigan absorbed the nearby city of Stambaugh and village of Mineral Hills in July 2000.
Minneapolis, Minnesota. St. Anthony (not to be confused with St. Anthony Village, a modern city which is a suburb) was a twin city to Minneapolis in the two cities' youth. Minneapolis annexed St. Anthony in the late 1800s.
Park Hills, Missouri was formed in 1994 by a four-way municipal merger involving the cities of Flat River, Elvins, and Esther, plus the village of Rivermines.
Jersey City, New Jersey, was incorporated in 1820, and slowly grew by annexing surrounding municipalities: Van Vorst Twp. (1851), Bergen City (1869), Hudson City (1869), Bergen Twp. (1869) and finally Greenville Twp. (1873).
New York City, New York (five boroughs, historically especially between Manhattan and Brooklyn)
What is now the city of Winston-Salem, North Carolina was once two separate towns called Winston and Salem that were combined into one.
Cleveland (Cleveland and Ohio City) in Ohio
Lincoln City, Oregon was formed in 1965 by merging the extant seaside towns of Oceanlake, Delake, and Taft, with the adjoining unincorporated areas of Nelscott and Cutler City.
Bethlehem, Pennsylvania, which absorbed the cities of South Bethlehem, and West Bethlehem. The former Bethlehem and South Bethlehem are situated in Northampton County, and West Bethlehem is in Lehigh County. As a result, present-day Bethlehem straddles the county line.
Pittsburgh, Pennsylvania, annexed Allegheny City, which is now the quarter of the city that lies north of the Allegheny and Ohio rivers. Also annexed was Birmingham, now referred to as the "South Side".
Richmond (Richmond and Manchester) in central Virginia
Bellingham, Washington was formed from four cities, Fairhaven, Sehome, Bellingham and Whatcom.
Fictional twin cities
Ankh-Morpork, from Terry Pratchett's Discworld novels, is referred to as "the twin cities of proud Ankh and pestilent Morpork"
Besźel and Ul Qoma in China Miéville's novel The City & the City are intertwined twin city-states in Eastern Europe whose inhabitants have trained themselves to only see the city they live in and unsee the city they don't.
Central City and Keystone City, from the current Flash comics, are shown as twin cities. Before the 1985-86 miniseries Crisis on Infinite Earths, Central and Keystone are presented as located in the same space but on different parallel Earths.
Duckburg and St. Canard were depicted in the cartoon Darkwing Duck as sister cities connected by a bridge, very similar to Oakland and San Francisco.
Gotham City (the home of Batman) and Metropolis (the home of Superman) have sometimes been presented as twin cities, mainly in 1970s and 1980s stories by DC Comics. In stories presenting them as twin cities, Gotham City and Metropolis are located on opposite sides of a large bay (identified as Delaware Bay in 1990's The Atlas of the DC Universe), with both cities linked by the Metro-Narrows Bridge, a suspension bridge resembling New York City's Verrazano-Narrows Bridge.
Helium, from the Barsoom series of novels by Edgar Rice Burroughs, consists of the twin cities Greater Helium and Lesser Helium.
See also
List of divided cities
Cross-border town naming
Megacity
List of metropolitan areas that overlap multiple countries