Merrimack County, New Hampshire Population 2026
Updated April 2026 · US Census ACS 2023 5-Year Estimates · 3rd-largest in New Hampshire
The population of Merrimack County, New Hampshire is 155,018 as of the 2023 American Community Survey, making it the 3rd-largest county in New Hampshire. The median household income is $93,944, the median home value is $330,600, and the median age is 42.6.
The population of Merrimack County has grown 7.8% since 2010 (146,395 → 157,869), a +0.54% annualized rate.
155,018
Population
+0.54%
Annual growth
166
People / sq mi
$93,944
Median Income
$330,600
Median Home Value
Merrimack County covers 933 sq mi of land at 166.2 people per square mile.
About Merrimack County, NH
Merrimack County is a county in New Hampshire with a population of 155,018. It ranks #3 among counties in New Hampshire by population. The median age is 42.6, older than the national median. The population is 49.8% male and 50.2% female.
The median household income in Merrimack County is $93,944, above the US median of $74,580. 3.7% of residents live below the federal poverty level. Home values sit at a median of $330,600, with monthly rent averaging $1,293. The homeownership rate of 73.5% is higher than the national rate of 64.8%.
Educational attainment in Merrimack County reflects 38.1% of adults 25 and older holding a bachelor's degree or higher, above the national average of 34.3%. Roughly 13.1% of workers primarily work from home, similar to the national work-from-home rate of 14.2%. The average commute is 27.0 minutes each way.
Merrimack County Population History (2010-2024)
The county of Merrimack County had a population of 146,395 in 2010 and 157,869 in 2024, a 7.8% growth over 14 years. The peak was 157,869 in 2024. Average annual growth rate: 0.54%.
157,869
Population (2024)
146,395
Population (2010)
157,869
Peak (2024)
0.54%
Avg Annual Growth
| Year | Population |
|---|---|
| 2010 | 146,395 |
| 2011 | 146,894 |
| 2012 | 147,149 |
| 2013 | 147,555 |
| 2014 | 148,252 |
| 2015 | 148,770 |
| 2016 | 149,246 |
| 2017 | 150,054 |
| 2018 | 150,981 |
| 2019 | 151,606 |
| 2020 | 154,039 |
| 2021 | 154,627 |
| 2022 | 156,241 |
| 2023 | 157,059 |
| 2024 | 157,869 |
Race & Ethnicity
| White | 91.4% |
| Black or African American | 1.6% |
| Asian | 0.0% |
| Hispanic or Latino (any race) | 1.1% |
| Two or More Races | 0.0% |
Age & Sex
42.6
Median Age
50.2%
Female
49.8%
Male
19.3%
Age 65+
Age Distribution
Children (under 15): 15.0% · Seniors (65+): 19.3%
Income & Poverty
| Median household income | $93,944$-1,684 vs state |
| Mean household income | $119,046 |
| Per-capita income | $47,056 |
| Poverty rate | 3.7%-0.7% vs state |
| Unemployment rate | 2.0% |
| Employment-to-population | 62.4% |
Top Industries by Employment
The largest employment sector in Merrimack County is professional & business services, accounting for 24.8% of workers.
How residents commute
0.3%
Drive alone
2.7%
Carpool
75.0%
Public transit
13.1%
Work from home
27.0 min
Avg commute
Housing
$330,600$-36,600 vs state
Median home value
$1,293
Median rent
73.5%
Homeownership rate
66,080
Total housing units
91.5%
Occupied
8.5%
Vacant
26.5%
Renter-occupied
Social & access
95.1%
With health insurance
95.0%
With broadband internet
41.5%
Foreign-born
8.1%
Veterans (18+)
14.5%
With a disability
94.8%
Speak language other than English at home
Education
93.7%
High School+
38.1%
Bachelor's+
Largest cities in New Hampshire
Other counties in New Hampshire
Part of New Hampshire
Metro areas in New Hampshire
County rankings
Frequently Asked Questions
Merrimack County, New Hampshire has a population of 155,018 according to the US Census Bureau's 2023 American Community Survey 5-year estimates, making it the 3rd-largest county in New Hampshire. Population density is 166 people per square mile.
The population of Merrimack County has grown 7.8% since 2010 (146,395 → 157,869), a +0.54% annualized rate.
The median household income in Merrimack County, New Hampshire is $93,944, with mean (average) household income of $119,046 and per-capita income of $47,056. 3.7% of residents live below the federal poverty level.
In Merrimack County, the largest racial and ethnic groups are White (91.4%), Black or African American (1.6%), Hispanic or Latino (1.1%). Figures are from the US Census Bureau's 2023 ACS 5-year estimates and reflect self-reported responses.
The median age in Merrimack County, New Hampshire is 42.6 years. Residents are 50.2% female and 49.8% male.
The median home value in Merrimack County is $330,600 and median monthly rent is $1,293. 73.5% of occupied housing units are owner-occupied. The county has 66,080 total housing units, 8.5% of which are vacant.
The largest employment sector in Merrimack County, New Hampshire is professional, scientific, and management services, employing 24.8% of workers. The unemployment rate is 2.0%.
Manchester is among the largest cities associated with Merrimack County, New Hampshire, with a population of 115,415.
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Full rankings of New Hampshire counties
Statewide data for New Hampshire
Population, race, income, age, and trends across New Hampshire
Data from the American Community Survey (ACS) 5-Year estimates.
Source: U.S. Census Bureau ACS, 2026.