Mercer County Flag

Mercer County

State:
New Jersey
County Seat:
Trenton

Mercer County's estimated 2026 population is 401,249 with a growth rate of 0.49% in the past year according to the most recent United States census data. Mercer County is the 12th largest county in New Jersey. The 2010 population was 367,717 and has seen a growth of 9.12% since that time.

401,249
Total Population
1,791
Population Density (mi²)
12
Population Rank (State)
2K 0.49%
Annual Population Growth

Mercer County Population

Demographics

Economics and Income Statistics