Jersey City is the second-most-populous city in the U.S. state of New Jersey, after Newark.

It is the seat of Hudson County as well as the county's largest city. As of 2016, the Census Bureau's Population Estimates Program calculated that Jersey City's population was 264,152, with the largest population increase of any municipality in New Jersey since 2010, an increase of about 6.7% from the 2010 United States Census, when the city's population was at 247,597, ranking the city the 77th-largest in the nation.

Part of the New York metropolitan area, Jersey City is bounded on the east by the Hudson River and Upper New York Bay and on the west by the Hackensack River and Newark Bay. A port of entry, with 30.7 miles (49.4 km) of waterfront and extensive rail infrastructure and connectivity, the city is an important transportation terminus and distribution and manufacturing center for the Port of New York and New Jersey.

Jersey City shares significant mass transit connections with Manhattan. Redevelopment of the Jersey City waterfront has made the city one of the largest centers of banking and finance in the United States and has led to the district being nicknamed Wall Street West.

After a peak population of 316,715 measured in the 1930 Census, the city's population saw a half-century-long decline to a low of 223,532 in the 1980 Census. Since then, the city's population has grown, with the 2010 population reflecting an increase of 7,542 (+3.1%) from the 240,055 counted in the 2000 Census, which had in turn increased by 11,518 (+5.0%) from the 228,537 counted in the 1990 Census.