Union City was incorporated as a city by an Act of the New Jersey Legislature on January 1, 1925, replacing both Union Hill and West Hoboken Township.
As of the census of 2000, there were 67,088 people, 22,872 households, and 16,056 families residing in the city. The population density was 20,395.9/km² (52,977.8/sq mi), extremely high for an American municipality, and in fact twice as high as New York City, although slightly less than Manhattan alone. Union City is the most densely populated city in the United States, though neighboring Guttenberg (a town) is more densely populated. There were 23,741 housing units at an average density of 7, 217.7/km² (18,747.7/sq mi). The racial makeup of the city was 58.38% White, 3.64% African American, 0.70% Native American, 2.15% Asian, 0.08% Pacific Islander, 28.19% from other races, and 6.87% from two or more races. Hispanic or Latino of any race were 82.32% of the population.
In the early days of the post-Revolution era, Union City boasted the nation's largest Cuban population, second only to Miami, Florida, leading to the nickname Havana on the Hudson. In the ensuing decades, Cuban residents have spread out to other communities of North Hudson County. West New York, at 19.64%, now has the highest percentage of Cubans in New Jersey, with Union City in second place, with 15.35%. These two municipalities having the highest Cuban population percentage in the United States, outside of Florida. Because of the still-high Cuban population, the major New York City television news outlets will invariably journey to Union City to interview citizens when news items involving Cuba or Fidel Castro arise. Moreover, Union City still boasts the largest Hispanic population percentage in New Jersey. It also has a very diversified Hispanic population with Cubans, Dominicans, and the more recent South Americans and Central Americans. Almost 60% of the population is foreign born, and 53% speak English less than "very well".
As of the 2000 census, 5.94% of Union City's residents identified themselves as being of Ecuadorian ancestry, which was the third highest of any municipality in New Jersey and the seventh highest percentage of Ecuadorian people in any place in the United States with 1,000 or more residents identifying their ancestry.
Most people live in two or three family houses and apartment buildings. There were 22,872 households out of which 36.6% had children under the age of 18 living with them, 42.4% were married couples living together, 19.3% had a female householder with no husband present, and 29.8% were non-families. 23.0% of all households were made up of individuals and 7.5% had someone living alone who was 65 years of age or older. The average household size was 2.92 and the average family size was 3.40. Union City is ranked #48 on a list of cities with the highest number of renters.
In the city the population was spread out with 25.3% under the age of 18, 11.0% from 18 to 24, 34.3% from 25 to 44, 19.4% from 45 to 64, and 10.0% who were 65 years of age or older. The median age was 32 years. For every 100 females there were 100.6 males. For every 100 females age 18 and over, there were 98.8 males.
As of 2000, Union City's employment breakdown is thus: 27% Manufacturing, 15% Professional, 15% Retail, 8% Transportation, 8% Finance/Insurance/Real Estate, 8% Wholesale Trade, 6% Business and Trade, 5% Construction, 4% Personal Service, 3% Public Administration, 3% Communications, and 1% Entertainment/Recreation.
The median income for a household in the city was $30,642, and the median income for a family was $32,246. Males had a median income of $25,598 versus $19,794 for females. The per capita income for the city was $13,997. About 18.6% of families and 21.4% of the population were below the poverty line, including 28.3% of those under age 18 and 19.3% of those age 65 or over. The Brookings Institute studies rank Union City among the 92 most economically depressed localities in the United States, with 18.1% of the population and 27.5% of the children falling below the poverty line. The New Jersey Municipal Distress Index, which is based on social, economic, fiscal and physical indicators, ranks Union City as the 3rd most distressed community in the state. Advocates for the homeless counted 2,227 people without homes in Hudson County as of January 2008.
The city is only two miles from New York City via the Lincoln Tunnel, one mile to the New Jersey Turnpike, four miles from the Garden State Parkway, and is situated at the junction of Route 495, Route 3, and U.S. Route 1/9.
Hudson-Bergen Light Rail (HBLR) service is available at the Bergenline Avenue station. HBLR is a light rail system, owned by New Jersey Transit and operated by the 21st Century Rail Corporation, that connects the Hudson County communities of Bayonne, Jersey City, Hoboken, Weehawken, Union City and North Bergen. Northbound service is available to Tonnelle Avenue. Southbound service is available to Hoboken Terminal and to stations along the routes to terminals at West Side Avenue in Jersey City and 22nd Street in Bayonne.
NJ Transit bus transportation is available to the Port Authority Bus Terminal in Midtown Manhattan on the 111, 121, 123, 124, 125, 127, 129, 154, 156, 159, 144, 190 (and the 108, 160, 161, 163, 167, 191, 192 by passenger request when heading to the Port Authority Bus terminal only), and the 195 (Saturdays only). The George Washington Bridge Bus Terminal is served by the 181. Jersey City can be reached on the 22, 82, 83, 84, 85, 86, 88 and 89 routes.
The closest airport in New Jersey with scheduled passenger service is Newark Liberty International Airport, located 12.5 miles away in Newark / Elizabeth. LaGuardia Airport in Flushing, Queens is 12.3 miles away via the Lincoln Tunnel. In addition, the Colombian airline Avianca operates a private bus service from John F. Kennedy Airport to Union City and Elizabeth for passengers on Avianca flights departing from and arriving to JFK.