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
The poverty rate is what most separates Merrimack County from the typical county: 3.7% of residents live below the federal poverty line, against 12.4% nationally. With 155,018 residents, Merrimack County is a county in New Hampshire. It is the #3-largest of all counties in New Hampshire nationally.
Earnings sit at the high end: a median household income of $93,944, above the US median of $78,538. Poverty is among the lowest of comparable US counties, at 3.7% — below the national 12.4%. Home values run above average at $330,600, with typical rent around $1,293.
Merrimack County is among the best-educated US counties: 38.1% of adults 25 and older hold a bachelor’s degree, above the national 35.0%. About 13.1% of workers primarily work from home, below the national 14.0%, and the average commute runs about 27 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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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.