Twin cities

Twin cities are a special case of two cities or urban centres which are founded in close geographic proximity and then grow into each other over time. The term Twin Cities in the United States refers specifically to the cities Minneapolis and Saint Paul, both of which are in the midwestern state of Minnesota.

Cities twinned geographically do not necessarily match demographically, economically, or politically.

In most cases, cities that grow into each other's space in this way lose their individual identities, and whatever border or barrier still separates them becomes irrelevant as they fuse into one new city. One famous example of this is Budapest in Hungary, which began as two settlements (Buda and Pest) facing each other across the Danube at a strategic fording place along a trade route. However, there are twin cities which have been able to resist this final union and have maintained individual identity against the tides of history, economics and demographics.

Twin cities often share an airport, into whose airport codes are integrated the initials of both cities; DFW (Dallas-Fort Worth), MSP (Minneapolis-St. Paul), and RDU (Raleigh-Durham) are examples.

In some cases, such as Albury/Wodonga in Australia, the two cities are permanently divided by a state border, often one that strictly adheres to a geographical landmark, such as the Murray River that divides New South Wales from Victoria, and thus Albury from Wodonga.

Asia

 * Kolkata and Howrah, India
 * Chiang Mai and Lamphun, Thailand
 * Guangzhou and Foshan, China
 * Hatyai and Songkhla, Thailand
 * Hong Kong and Shenzhen, China
 * Macau and Zhuhai, China
 * Ramallah and al-Bireh, in the West Bank
 * Seoul and Incheon, South Korea
 * Tel Aviv and Jaffa, Israel
 * Taipei and Keelung, Republic of China (Taiwan)
 * Taoyuan and Jhongli, Republic of China (Taiwan)
 * Ahmedabad and Gandhinagar in Gujarat State of India are looked upon as merging into a new twin city in-the-process.
 * Hyderabad and Secunderabad, India
 * Surat and Navsari in Gujarat State of India are in the process of merging and will be completed by 2015.
 * Sangli and Miraj, India
 * Udhana and Sachin, Gujarat In Gujarat are one of the first Twin Cities in India.
 * Islamabad and Rawalpindi, Pakistan
 * Jhelum and Sarai Alamgir, Pakistan
 * Dhaka and Gazipur, Bangladesh
 * Ernakulam-Kochi and Thrissur, India, now are in the process of merging and will be completed by 2020.
 * Bhubaneswar and Cuttack, India
 * Hubli and Dharwad, India
 * Mumbai, Navi Mumbai and Thane, India
 * Tirunelveli and Palayamkottai, India
 * Pune and Pimpri-Chinchwad, India
 * Mandla and Balaghat, Madhya Pradesh, India
 * Dipolog and Dapitan, Philippines
 * Johor Bahru and Singapore

Europe

 * Brighton and Hove, England
 * Chatham and Rochester, England "it's a wise man who knows where Chatham ends and Rochester begins." Charles Dickens
 * Manchester and Salford, England
 * Copenhagen, Denmark and Malmö, Sweden, often referred to as twin cities, as part of the Öresund Region, divided by the Øresund strait.
 * Göteborg and Mölndal, Sweden
 * Ludwigshafen and Mannheim, Germany
 * Ulm and Neu-Ulm, Germany
 * Mainz and Wiesbaden, Germany
 * Porsgrunn and Skien, Norway
 * Sandnes and Stavanger, Norway
 * Fredrikstad and Sarpsborg, Norway
 * Gorizia, Italy and Nova Gorica, Slovenia
 * Gornja Radgona, Slovenia and Bad Radkersburg, Austria
 * Buda and Pest, Hungary
 * Tornio, Finland and Haparanda, Sweden
 * Porto and Vila Nova de Gaia, Portugal
 * Zgorzelec, Poland and Görlitz, Germany
 * Těšín, Czech Republic and Cieszyn, Poland
 * Aalborg and Nørresundby, Denmark
 * Alcobendas and San Sebastian de los Reyes in Madrid, Spain
 * Valka, Latvia and Valga, Estonia
 * Komárno, Slovakia and Komárom, Hungary
 * Newcastle-upon-Tyne and Sunderland, United Kingdom

North America

 * Minneapolis and Saint Paul, Minnesota, popularly known as the "Twin Cities" in North America
 * San Francisco and Oakland, California
 * Philadelphia, Pennsylvania, and Camden, New Jersey
 * Hartford, Connecticut and Springfield, Massachusetts, also known as the Knowledge Corridor, is the second most populous metropolitan region in New England with 1.9 million people.
 * Baltimore, Maryland and Washington, D.C. as part of the Baltimore–Washington Metropolitan Area, a megalopolis with many other component cities and towns, including many in the State of Virginia.
 * Dallas, and Fort Worth, Texas, the main cities of the Dallas–Fort Worth Metroplex, a megalopolis in northeastern Texas.
 * Raleigh, and Durham, North Carolina, the two main cities of the three city Research Triangle area.
 * Ottawa, Ontario and Gatineau, Quebec are the two main cities of Canada's National Capital Region
 * San Bernardino and Riverside, California, the central cities of the area popularly known as the Inland Empire.
 * Fargo, North Dakota and Moorhead, Minnesota, together referred to as Fargo–Moorhead
 * Detroit, Michigan and Windsor, Ontario
 * Jersey City and Newark, New Jersey
 * Columbus, Georgia, and Phenix City, Alabama, separated by the Chattahoochee River.
 * Duluth, Minnesota, and Superior, Wisconsin, often referred to as the "Twin Ports"
 * Halifax, Nova Scotia and Dartmouth, Nova Scotia. Even though both cities were merged into the Halifax Regional Municipality they are geographically separated by Halifax Harbour and still retain separate identities.
 * Monroe, Louisiana and West Monroe, Louisiana
 * Kansas City, Kansas and Kansas City, Missouri
 * South Bend and Mishawaka, Indiana
 * Niagara Falls, Ontario and Niagara Falls, New York
 * Mount Vernon, Iowa and Lisbon, Iowa
 * Lewiston and Auburn, Maine, sometimes locally referred to as "LA" or as the Twin Cities.
 * Houghton and Hancock, Michigan
 * Utica and Rome, New York
 * Brownsville, Texas and Matamoros, Tamaulipas
 * Laredo, Texas and Nuevo Laredo, Tamaulipas
 * Bluefield, Virginia and Bluefield, West Virginia
 * Bloomington and Normal, Illinois
 * Bristol, Virginia and Bristol, Tennessee, part of the Tri-Cities, Tennessee area — named for Bristol as a whole, Kingsport, and Johnson City, Tennessee.
 * Nogales, Arizona and Nogales, Sonora
 * Texarkana, Texas and Texarkana, Arkansas
 * Kenai and Soldotna, Alaska
 * Sault Ste. Marie, Michigan and Sault Ste. Marie, Ontario
 * Gulfport and Biloxi, Mississippi
 * Portland, Oregon and Vancouver, Washington
 * Seattle and Tacoma, Washington
 * Reno and Sparks, Nevada
 * Bismarck and Mandan, North Dakota, also known as Sister Cities to local residents.
 * Lancaster and Palmdale, California
 * Fort Myers and Cape Coral, Florida
 * Denver and Aurora, Colorado
 * Delmar, Delaware and Delmar, Maryland
 * Marydel, Delaware and Marydel, Maryland
 * McAllen, Texas and Reynosa, Tamaulipas
 * Grand Forks, North Dakota and East Grand Forks, Minnesota
 * Eureka and Arcata, California
 * Lewiston, Idaho and Clarkston, Washington, named after the explorers who first visited the region.
 * Scranton and Wilkes-Barre, Pennsylvania
 * High Point and Greensboro, North Carolina, two of the three cities that are the focal points of the Piedmont Triad
 * Prairie du Sac and Sauk City, Wisconsin, commonly referred to as Sauk Prairie, Wisconsin
 * Urbana and Champaign, Illinois — see also Champaign–Urbana Metropolitan Area and University of Illinois at Urbana–Champaign
 * Allentown and Bethlehem, Pennsylvania, the main cities of the Lehigh Valley metropolitan area.
 * Easton, Pennsylvania and Phillipsburg, New Jersey
 * Kitchener and Waterloo, Ontario
 * Veracruz, Veracruz and Boca del Río, Veracruz
 * Fulton, Kentucky and South Fulton, Tennessee
 * Colorado City, Arizona and Hildale, Utah, best known as the historic center of the Fundamentalist Church of Jesus Christ of Latter Day Saints, a polygamous offshoot of the Latter Day Saint movement
 * Helena and West Helena, Arkansas were twin cities before a 2006 merger formed the current city of Helena-West Helena.
 * Gering and Scottsbluff, Nebraska
 * Eau Claire and Altoona, Wisconsin.
 * Tampa, Florida and Saint Petersburg, Florida

South America

 * Leticia, Colombia and Tabatinga, Brazil.
 * Rivera, Uruguay and Santana do Livramento, Brazil.
 * Vitória and Vila Velha, Brazil.
 * Aparecida and Guaratinguetá, Brazil.
 * Florianópolis and São José, Brazil.
 * Juazeiro and Petrolina, Brazil.
 * Recife and Olinda, Brazil.
 * Ilhéus and Itabuna, Brazil.
 * Foz do Iguaçu, Brazil, Puerto Iguazu, Argentina, and Ciudad del Este, Paraguay.
 * Valparaiso and Viña del Mar, Chile.
 * La Serena and Coquimbo, Chile.
 * Concepción and Talcahuano, Chile.
 * Barranquilla and Soledad, Colombia.
 * Lima and Callao, Peru.
 * Santa Fe and Paraná, Argentina.
 * Carmen de Patagones and Viedma, Argentina.

Australia

 * Albury and Wodonga
 * Canberra and Queanbeyan
 * Coolangatta and Tweed Heads
 * Forster and Tuncurry

Africa

 * Fes and Meknes, Morocco
 * Kinshasa, capital of Congo DR and Brazzaville, capital of Republic of the Congo
 * Cairo and Giza, Egypt
 * Harar and Dire Dawa, Ethiopia

Fictional twin cities

 * 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. The two cities were shown as located on opposite sides of a large bay.
 * Central City and Keystone City, from the current Flash comics, are shown as twin cities; earlier comics presented each city as located in the same space but on different parallel Earths.
 * Ankh-Morpork, from Terry Pratchett's Discworld novels, is referred to as "the twin cities of proud Ankh and pestilent Morpork"
 * 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.

United States

 * In Iowa: Cedar Rapids, Marion and Hiawatha
 * The Tri-Cities, Washington, consisting of Richland, Pasco, and Kennewick, Washington, along the banks of the Columbia River
 * The Tri-Cities, Tennessee, Tennessee and Virginia, consisting of the twin cities of Bristol, Tennessee/Bristol, Virginia, Kingsport, and Johnson City
 * The Research Triangle in North Carolina, consisting of Raleigh, Durham, and Chapel Hill.
 * The Golden Triangle in Texas, consisting of Beaumont, Port Arthur, and Orange.
 * The Piedmont Triad in North Carolina, consisting of Greensboro, Winston-Salem (itself a merged city), and High Point.
 * The Tri-Cities in Michigan, consisting of Bay City, Saginaw, and Midland in the Saginaw Valley
 * In Illinois and Iowa: three of the four Quad Cities—Moline and Rock Island in Illinois and Davenport in Iowa—were formerly known as the Tri-Cities, before the inclusion of East Moline, Illinois and later, Bettendorf, Iowa
 * In Kane County, Illinois, the county seat of Geneva and the nearby cities of Batavia, and St. Charles,
 * The Capital District in New York, consisting of Albany, Schenectady, and Troy
 * In Colorado: the towns of Firestone, Frederick, and Dacono (known as the "tri-towns")
 * In Nebraska:
 * in the south-central part of the state, Grand Island, Kearney, and Hastings
 * in the panhandle, western part of the state, Gering, Scottsbluff and Terrytown are border to border
 * Tri-Cities, Virginia, consisting of Petersburg, Colonial Heights, and Hopewell in the Greater Richmond Region
 * In New Hampshire: Dover, Somersworth, and Rochester in the Seacoast Region
 * In Florida:
 * In the southeast of the state, South Florida, consisting of the anchor cities of Miami, Fort Lauderdale, and West Palm Beach. This region is sometimes referred to as the tri-county area (Dade, Broward, and Palm Beach counties)
 * On the Gulf of Mexico Coast, the Tampa Bay Area, consisting of Tampa, Clearwater, and St. Petersburg
 * In Oklahoma: Tuttle, Newcastle, and Blanchard (sometimes with the town of Bridge Creek)
 * In California:
 * In Alameda County: Fremont, Newark, and Union City are referred to as the Tri-City Area.
 * In Santa Barbara County: Santa Barbara, Goleta, and Carpinteria, sometimes referred collectively as the South Coast. The term 'tri-cities' is only rarely used as a reference to them, and is considered somewhat old.
 * In San Diego County: Oceanside, Vista, and Carlsbad are sometimes referred to as the tri-cities.
 * The Triple Cities in New York: Binghamton, Endicott and Johnson City
 * The Lehigh Valley in Pennsylvania: Allentown, Bethlehem, and Easton
 * In Alabama: Huntsville, Decatur, and Athens

Canada

 * Tri-Cities (British Columbia), consisting of Coquitlam, Port Coquitlam, and Port Moody, located in the north-eastern section of Metro Vancouver.
 * Penetanguishene, Victoria Harbour, Midland, and Port McNicoll, Ontario.
 * Ingersoll, Tillsonburg and Woodstock, Ontario.
 * Kitchener, Waterloo and Cambridge, Ontario.

Mexico

 * Torreón, Coahuila, Gómez Palacio and Lerdo, Durango — see also Comarca Lagunera
 * Monterrey and San Nicolás de los Garza, Nuevo León
 * Monterrey and San Pedro Garza García
 * Monterrey and Guadalupe, Nuevo León
 * Monterrey and Escobedo, Nuevo León
 * Monterrey and Santa Catarina, Nuevo León
 * Saltillo and Ramos Arizpe, Coahuila
 * Piedras Negras, Coahuila and Eagle Pass, Texas
 * Ciudad Acuña, Coahuila and Del Rio, Texas

Asia

 * Arcot, Ranipet and Walajapet towns in Tamil Nadu
 * Warangal in India, Andhra Pradesh consists of the towns of Warangal, Hanamakonda, and Kazipet.
 * The second Tricity in North India consists of the towns of Chandigarh, Panchkula and SAS Nagar (Mohali).
 * Tricity of Nepal consists of the cities of Baglung, Beni and Kushma along with several towns and villages along the Kali Gandaki valley.

South America

 * Near Iguazu Falls: Foz do Iguaçu, Brazil, Ciudad del Este, Paraguay, and Puerto Iguazu, Argentina.

Europe

 * The Tricity in Poland consists of Gdańsk, Gdynia and Sopot
 * The cities of Oxford, Cambridge and London are sometimes considered as a tricity of scientific excellence connected by good rail or road connections.

Quad cities

 * In Iowa: Iowa City, Coralville, University Heights and North Liberty
 * The Quad Cities of Ontario, Canada include Kitchener and Waterloo, and Cambridge and Guelph, Ontario.
 * Quad Cities of Davenport and Bettendorf, Iowa, and Rock Island and Moline, Illinois. It also includes a fifth member, East Moline, Illinois.
 * The Florence-Muscle Shoals Metropolitan Area in Alabama is locally referred to as "the Quad Cities", with Florence, Muscle Shoals, Sheffield, and Tuscumbia. Formerly, when Muscle Shoals was a mere village, this region was known a "Tri-Cities", Alabama. Actually, they are all incorporated as towns except for Florence.
 * The Quad Cities of Minnesota consist of Virginia, Eveleth, Gilbert, and Mountain Iron.
 * 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

Europe

 * London grew from its cores in London Town and the City of Westminster to encompass many other towns and villages.
 * Budapest is the amalgamation of Buda, Pest and Óbuda.
 * 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

North America

 * Richmond (Richmond and Manchester) in central Virginia
 * Cleveland (Cleveland and Ohio City) in Ohio
 * Minneapolis. St. Anthony (not to be confused with St. Anthony Village, a modern city which is a suburb of Saint Paul) was a twin city to Minneapolis in the two cities' youth. Minneapolis annexed St. Anthony in the late 1800s.
 * New York City (five boroughs, historically especially between Manhattan and Brooklyn)
 * 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.
 * Birmingham, Alabama, was formed in 1871 by the merger of three neighboring towns. Over its first century, Birmingham repeatedly absorbed neighboring towns and villages, including places like North Birmingham.
 * What is now the city of Winston-Salem, North Carolina was once two separate towns called Winston and Salem that were combined into one.
 * Ottawa, Ontario, 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
 * Gatineau, Quebec, 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.
 * Toronto, Ontario, formed by an amalgamation of the old City of Toronto with East York, Etobicoke, North York, Scarborough and York - which were themselves products of earlier amalgamations.
 * Thunder Bay, Ontario (Fort William and Port Arthur).
 * 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.
 * Halifax and Dartmouth (Canada) were forcibly merged in 1996 along with Bedford and Halifax County to create the Halifax Regional Municipality.
 * Saguenay, Quebec (Chicoutimi, Jonquière, et al.)
 * Seattle annexed the neighboring towns of West Seattle and Ballard.
 * 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.
 * Pittsburgh annexed Allegheny City, which is now the quarter of the city that lies north of the Allegheny and Ohio rivers.
 * Ciudad Guayana, Venezuela, officially founded in 1961 is actually composed of the old town of San Félix at the east and the new modern planned town of Puerto Ordaz at the west of Caroní river in Bolívar state.
 * Bethlehem, Pennsylvania, which absorbed the cities of South Bethlehem, and West Bethlehem. The former Bethlehem and South Bethlehem are situated in Northampton County, Pennsylvania, and West Bethlehem is in Lehigh County.  As a result, present-day Bethlehem straddles the county line.
 * Montreal, Quebec, was merged with the other 27 communities on the Island of Montreal by an act in the Quebec Parliament in 2002. Several communities later voted via referendum to de-merge and there are now a total of 15, leaving Montreal merged with the other 12.
 * Kingston, Ontario was amalgamated in 1998 with the neighboring Kingston and Pittsburgh Townships.
 * Winnipeg, Manitoba, in 1971 was the first major North American city to be amalgamated in what was known as Unicity. The centralized city of Winnipeg was merged with all of its suburbs (12 other communities and municipalities), more than doubling its population. See also Subdivisions of Winnipeg
 * Helena-West Helena, Arkansas was formed in 2006 by the merger of the previous cities of Helena and West Helena.

Asia & Australia

 * Hong Kong (Victoria City and Kowloon)
 * Townsville (Townsville and Thuringowa) in Queensland, Australia
 * Wuhan in China consists of the towns of Wuchang, Hankou, and Hanyang in Hubei Province