Mercer County, New Jersey Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 12th-largest in New Jersey
The population of Mercer County, New Jersey is 383,286 as of the 2023 American Community Survey, making it the 12th-largest county in New Jersey. The median household income is $96,333, the median home value is $351,000, and the median age is 39.2.
The population of Mercer County has grown 6.6% since 2010 (367,717 → 392,138), a +0.46% annualized rate.
383,286
Population
+0.46%
Annual growth
1707
People / sq mi
$96,333
Median Income
$351,000
Median Home Value
Mercer County covers 224 sq mi of land at 1707.4 people per square mile.
About Mercer County, NJ
What distinguishes Mercer County is density: among the most densely settled of US counties, around 1,707 people per square mile. With 383,286 residents, Mercer County is a county in New Jersey. It ranks #12 among counties in New Jersey by population.
Income is a real outlier — the median household pulls in $96,333, putting Mercer County near the top of US counties. The poverty rate is 7.5%, below the national 12.4%. Home values run above average at $351,000, with typical rent around $1,515.
Mercer County is among the best-educated US counties: 44.9% of adults 25 and older hold a bachelor’s degree, above the national 35.0%. Working from home is common here: 17.8% of workers do so, above the national 14.0%, and the average commute runs about 28 minutes each way.
That density explains much of the rest of the profile in Mercer County: denser places lean toward renting, shorter commutes by transit, and a younger working-age mix.
Mercer County Population History (2010-2024)
The county of Mercer County had a population of 367,717 in 2010 and 392,138 in 2024, a 6.6% growth over 14 years. The peak was 392,138 in 2024. Average annual growth rate: 0.47%.
392,138
Population (2024)
367,717
Population (2010)
392,138
Peak (2024)
0.47%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 367,717 |
| 2011 | 367,407 |
| 2012 | 368,628 |
| 2013 | 369,534 |
| 2014 | 369,031 |
| 2015 | 368,266 |
| 2016 | 367,929 |
| 2017 | 368,489 |
| 2018 | 368,720 |
| 2019 | 368,047 |
| 2020 | 386,492 |
| 2021 | 382,231 |
| 2022 | 382,165 |
| 2023 | 386,296 |
| 2024 | 392,138 |
Race & Ethnicity
| White | 49.8% |
| Black or African American | 19.2% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 1.4% |
| Two or More Races | 0.0% |
Age & Sex
39.2
Median Age
50.6%
Female
49.4%
Male
15.7%
Age 65+
Age Distribution
Children (under 15): 18.0% · Seniors (65+): 15.7%
Income & Poverty
| Median household income | $96,333$-4,717 vs state |
| Mean household income | $138,732 |
| Per-capita income | $52,101 |
| Poverty rate | 7.5%+0.5% vs state |
| Unemployment rate | 3.9% |
| Employment-to-population | 60.2% |
Top Industries by Employment
The largest employment sector in Mercer County is professional & business services, accounting for 26.7% of workers.
How residents commute
5.2%
Drive alone
3.5%
Carpool
61.5%
Public transit
17.8%
Work from home
27.6 min
Avg commute
Housing
$351,000$-76,600 vs state
Median home value
$1,515
Median rent
61.9%
Homeownership rate
150,600
Total housing units
93.9%
Occupied
6.1%
Vacant
38.1%
Renter-occupied
Social & access
92.4%
With health insurance
95.1%
With broadband internet
21.6%
Foreign-born
3.6%
Veterans (18+)
10.1%
With a disability
65.2%
Speak language other than English at home
Education
89.9%
High School+
44.9%
Bachelor's+
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County rankings
Common questions about Mercer County, NJ
Frequently Asked Questions
Mercer County, New Jersey has a population of 383,286 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 12th-largest county in New Jersey. Population density is 1707 people per square mile.
The population of Mercer County has grown 6.6% since 2010 (367,717 → 392,138), a +0.46% annualized rate.
The median household income in Mercer County, New Jersey is $96,333, with mean (average) household income of $138,732 and per-capita income of $52,101. 7.5% of residents live below the federal poverty level.
In Mercer County, the largest racial and ethnic groups are White (49.8%), Black or African American (19.2%), Hispanic or Latino (1.4%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Mercer County, New Jersey is 39.2 years. Residents are 50.6% female and 49.4% male.
The median home value in Mercer County is $351,000 and median monthly rent is $1,515. 61.9% of occupied housing units are owner-occupied. The county has 150,600 total housing units, 6.1% of which are vacant.
The largest employment sector in Mercer County, New Jersey is professional, scientific, and management services, employing 26.7% of workers. The unemployment rate is 3.9%.
Newark is among the largest cities associated with Mercer County, New Jersey, with a population of 307,188.
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Statewide data for New Jersey
Population, race, income, age, and trends across New Jersey
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.