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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).
Zambia / Zimbabwe
- Halifax and Dartmouth in Nova Scotia[n 2]
- Kitchener and Waterloo, Ontario
- Battleford and North Battleford, Saskatchewan "The Battlefords" [n 3]
- Texarkana, Arkansas and Texarkana, Texas[n 4]
- Hartford and New Britain, Connecticut
- Fort Myers and Cape Coral, Florida
- Fort Lauderdale and Miami
- St. Petersburg and Tampa, Florida[n 5]
- Champaign and Urbana, Illinois[n 6]
- Bloomington and Normal, Illinois
- Lewiston and Auburn, Maine[n 7]
- Houghton and Hancock, Michigan.
- Duluth, Minnesota, and Superior, Wisconsin[n 8]
- Minneapolis and Saint Paul, Minnesota[n 9]
- Natchez, Mississippi and Vidalia, Louisiana[n 10]
- Crystal City, Missouri and Festus, Missouri
- 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[n 11]
- Grand Forks, North Dakota and East Grand Forks, Minnesota
- Portland, Oregon and Vancouver, Washington
- Scranton and Wilkes-Barre, Pennsylvania[n 12]
- Allentown and Bethlehem, Pennsylvania
- Greenville and Spartanburg, South Carolina[n 13]
- Bristol, Tennessee and Bristol, Virginia
- Dallas and Fort Worth, Texas[n 14]
- Midland and Odessa, Texas[n 15]
- Bluefield, Virginia and Bluefield, West Virginia
- Memphis, Tennessee and West Memphis, Arkansas
- Fort Collins and Loveland, Colorado
Examples, sharing names or similar names, across an international border include:
- Canada–United States border
- 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
- United States–Canada border
- 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
- Lloydminster, Alberta/Saskatchewan, Canada[n 16]
- Thunder Bay, Ontario, Canada[n 17]
- Saginaw and East Saginaw, Michigan, United States[n 18]
- Brooklyn and New York City, New York, United States[n 19]
- Americana, São Paulo and Santa Bárbara d'Oeste
- Juazeiro and Petrolina
- Olinda and Recife
- Vila Velha and Vitória
- Mainland China
- Hong Kong
- Ahmedabad and Gandhinagar, India
- Allahabad and Naini, India
- Aurangabad and Jalna, India
- Bangalore and Hosur, 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
- 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
- Pallavaram and Chromepet, 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
- Aomori and Hakodate, Japan
- Kamisu and Kashima, Japan[n 21]
- Kitakyushu and Shimonoseki, Japan
- Kyoto and Otsu, Japan
- Maebashi and Takasaki, Japan
- Nasushiobara and Otawara, Japan[n 22]
- Okayama and Kurashiki, Japan[n 23]
- Osaka and Sakai, Japan[n 24]
- Sanjo and Tsubame, Japan
- Toyohashi and Toyokawa, Japan
- Tsukuba and Tsuchiura, Japan[n 25]
- Yokkaichi and Suzuka, Japan
- North Korea
- Saudi Arabia
- South Korea
- 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
- 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.
- 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
- Austria–Slovakia border
- Austria–Slovenia border
- Belgium–France border
- Croatia–Bosnia and Herzegovina border
- Czech Republic–Poland border
- Denmark–Sweden border
- Estonia–Latvia border
- Estonia–Russia border
- Finland–Russia border
- Finland–Sweden border
- France–Germany border
- France–Spain border
- Germany–Poland border
- Germany–Switzerland border
- Laufenburg (Baden), Germany and Laufenburg,_Aargau, Switzerland, separated between the Rhine River (used to be one city until 1801/1802).
- Hungary–Slovakia border
- Ireland–United Kingdom border
- Italy–Slovenia border
- The Netherlands–Germany border
- Spain–Gibraltar border
- Switzerland–Germany-France border
- 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.
- 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.
- 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
- 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
- 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
- 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[n 26]
- 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
- 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
- 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.
- The Michiana area, in the states of Indiana and Michigan, consisting of the cities of South Bend, Mishawaka, Elkhart, Granger, Michigan City, Goshen, La Porte (Indiana), New Buffalo, Buchanan, Niles, Berrien Springs, St. Joseph, Benton Harbor, and Dowagiac (Michigan)
- 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
- 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.
- The Netherlands
- 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.
- 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.[n 27]
- 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.
- List of divided cities
- Cross-border town naming
- List of metropolitan areas that overlap multiple countries
- Sister city
- Separated by the Zambezi River at the location of Victoria Falls, each city benefits from tourism created by Victoria Falls, the largest waterfall in the world as measured by combined height and width (see Victoria Falls Size). The primary airport of the region, Harry Mwanga Nkumbula International Airport, is located in Livingstone and brings tourists from all over the world. The two cities share an international border that is located halfway across the Victoria Falls Bridge, which was completed in 1905.
- Main cities of Metropolitan Halifax, they are geographically separated by Halifax Harbour
- Separated by the North Saskatchewan River. While the communities are commonly referred to by the collective "The Battlefords," they retain distinctive identities.
- The cities meet at the border between Texas and Arkansas, and their name is a portmanteau of those states' names as well as that of Louisiana, whose border lies approximately 25 miles to the south. See Texarkana metropolitan area and Ark-La-Tex.
- Main cities of the Tampa Bay Area.
- Champaign was originally known as West Urbana but has since outgrown its neighbor. See Champaign–Urbana metropolitan area.
- Also called the Twin Cities or L–A. See Lewiston–Auburn
- Nicknamed the Twin Ports, these form the world's largest freshwater port.
- Also known as the Twin Cities
- The cities are connected by two twin cantilever bridges which merge the two cities together as sister cities. The cities meet on the Mississippi and Louisiana state border and along the Mississippi River adjacent to each other. They both share long history together. Natchez, Mississippi is also a historical part of Concordia Parish, Louisiana, to which Vidalia is the seat of Concordia Parish. See Natchez–Vidalia Bridge, Concordia Parish and Adams County, Mississippi.
- See Fargo–Moorhead.
- The core cities of the Wyoming Valley in northeastern Pennsylvania.
- The two largest cities of Upstate South Carolina. Their shared international airport is named after both cities (Greenville–Spartanburg International Airport).
- Twin cores of the Metroplex of northern Texas.
- Nicknamed the Petroplex in a nod to the DFW region's nickname, as well as its strong reliance on the oil industry.
- Until 1930, the community, divided by the Alberta-Saskatchewan border, was two separate, adjacent towns. However, with the Town of Lloydminster Acts in administration the large town became integrated while still bi-provincial.
- Formed by the amalgamation of Fort William and Port Arthur, Ontario in 1970.
- East Saginaw annexed by Saginaw in 1889.
- Prior to their consolidation into a single city in 1898 - as noted in the poem "The New Colossus", which is inscribed on a plaque at the Statue of Liberty.
- Formed historic Al-Mada'in.
- Co-centers of a shared micropolitan area.
- Co-centers of a shared micropolitan area.
- Kurashiki is somewhat more of a suburb
- Co-centers of a shared major metropolitan area. See Keihanshin
- Co-centers of a shared major metropolitan area.
- the principal cities of the San Francisco Bay area.
- Nicknamed the Twin City.
- "10 Twin Towns and Sister Cities of Indian States". walkthroughindia.com. Retrieved 9 January 2014.
- "10 Twin Towns and Sister Cities of Indian States". walkthroughindia.com. Retrieved 9 January 2014.
- Weather story from 2006 The Hindu Business Line. Retrieved 2006-12-31
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- "It's a wise man who knows where Chatham ends and Rochester begins." Charles Dickens
- "Tricity residents to get Emaar MGF's Central Plaza soon". The Financial Express. Jan 6, 2014.
- "Quad Cities too generic a name for ID, WA cities". The Seattle Times. 28 April 2010. Retrieved 22 January 2013.
- "Juan Manuel Grijalvo - Madrid - Barrios desaparecidos y actuales - Antiguos municipios independientes".
- See e.g. the introduction of The Hogfather q:Terry Pratchett's Hogfather
- The Flash (volume 1) #123, DC Comics, September 1961
- Starr, Joe (2015-08-05). "Nerd Rabbit Hole: A Guide To Disney's Duck Universe". Pajiba. Retrieved 2018-05-10.
- "San Francisco–Oakland Bay Bridge". www.visitcalifornia.com. Retrieved 2018-05-10.
- Action Comics #451, DC Comics, September 1975
- New Adventures of Superboy #22, DC Comics, October 1981
- World's Finest Comics #259, DC Comics, October–November 1979
- Burroughs, Edgar Rice (1917). A Princess of Mars. A. C. McClurg & Co. pp. 279–80, 305, 313–14.