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Where am ILOCATED

Trenton-Princeton, NJ Metro Area

The Trenton-Princeton, NJ metro area is one county in New Jersey: Mercer County. About 399,289 people lived there on July 1, 2025 (Census estimate), 3.1% more than in April 2020.

Mercer County, centralTrentonPrinceton
Mercer County in New Jersey
Population, July 2025
399,289 3.1% more than in April 2020
Type
Metropolitan statistical area
County
Mercer County
Land area
224 sq mi (581 km²)
Time zone
Eastern TimeUTC-05:00 in January; UTC-04:00 in July
State
New Jersey
Combined statistical area
New York-Newark, NY-NJ-CT-PA
CBSA code
45940
Open this area in the metro area finder

The county in the Trenton-Princeton, NJ metro area

CountyRolePopulation, July 2025
Mercer CountyCentral399,289

A central county holds the area’s core, an urban area of at least 50,000 people. This area has no outlying counties: no neighboring county sends enough commuters to join it. A county belongs to one metro or micro area at most, and it counts whole, countryside included.

Principal cities, largest first

  1. Trenton90,338 people
  2. Princeton30,756 people

OMB names the area after its largest principal cities. A principal city is the area’s largest city, plus any other city that is very large or a big job center, and smaller ones with at least as many jobs as working residents (2020 Census and commuting figures). People counts are American Community Survey 2020–2024 5-year estimates.

Part of the New York-Newark, NY-NJ-CT-PA combined statistical area

OMB joins neighboring metro and micro areas into a combined statistical area when enough people commute between them. The other 6 areas in this one, largest first:

  1. New York-Newark-Jersey City, NY-NJ Metro Area20,112,448 people
  2. Bridgeport-Stamford-Danbury, CT Metro Area978,179 people
  3. Kiryas Joel-Poughkeepsie-Newburgh, NY Metro Area718,377 people
  4. Kingston, NY Metro Area183,330 people
  5. Monticello, NY Micro Area80,586 people
  6. Hemlock Farms, PA Micro Area62,808 people

Bordering metro and micro areas, nearest first

Areas with a county on this area’s edge. Distances are straight lines between the areas’ largest cities.

  1. Philadelphia-Camden-Wilmington, PA-NJ-DE-MD Metro Area25 mi southwest
  2. New York-Newark-Jersey City, NY-NJ Metro Area53 mi northeast

Before using this answer on a form

A metro or micro area is a statistical area that OMB draws for federal statistics. It is not a city, a local government or a mailing address, and it is not a measure of urban and rural: whole counties count, rural parts included. Programs that use metro areas, such as housing income limits or wage rates, can use their own version of these lists; check the program’s own list for an address.

Find the metro area where you are now, find your county, or see every metro and micro area by population.

See this area on Census.gov ↗