Demographics of Merrimack County, New Hampshire

Merrimack County, New Hampshire had 158,078 people on July 1, 2025, by the Census Bureau’s estimate: +4,017 since July 2020. Age, income, poverty, housing and origin below come from the American Community Survey, averaged over 2020–2024, each with its margin of error.

Merrimack County, in four figures

158,078
Population: July 1, 2025, Vintage 2025 estimate.; +2.6%
Change since July 2020: +4,017 people.; 42.9 ±0.3
Median age: ACS 2020–⁠2024.; $97,004 ±$2,796
Median household income: ACS 2020–⁠2024, in 2024 dollars.

Population, year by year

July 1 estimates from the Census Bureau’s Vintage 2025. Each year's change is births less deaths, net moves from abroad and net moves from elsewhere in the country, with the Bureau's small residual. The 2020 row's components run 3 months, from the April census to July 1.

Merrimack County, New Hampshire's population grew 2.6% from July 2020 to July 2025, against +3.1% nationally

The July 1 estimate of Merrimack County, New Hampshire's resident population and the nation's, each year of the Census Bureau's Vintage 2025, as a share of its July 2020 level (= 100).

Source: The Census Bureau

About this chart

The figures

Merrimack County, New Hampshire's population grew 2.6% from July 2020 to July 2025, against +3.1% nationally. The July 1 estimate of Merrimack County, New Hampshire's resident population and the nation's, each year of the Census Bureau's Vintage 2025, as a share of its July 2020 level (= 100).
July 1	Population	Index	United States
2020	154,061	100.0	100.0
2021	154,660	100.4	100.2
2022	156,220	101.4	100.7
2023	156,883	101.8	101.6
2024	157,547	102.3	102.5
2025	158,078	102.6	103.1

3 more columns on a wider screen

Population of Merrimack County, New Hampshire on July 1 of each year, Vintage 2025
July 1	Population	Change	Births less deaths	From abroad	From elsewhere in the country
2020	154,061	+245	−42	+12	+249
2021	154,660	+599	−203	+152	+499
2022	156,220	+1,560	−319	+75	+1,787
2023	156,883	+663	−383	+170	+881
2024	157,547	+664	−421	+217	+858
2025	158,078	+531	−411	+130	+810

Age, 2020–2024

The median age is 42.9 ±0.3: for men 41.8 ±0.4 and for women 43.9 ±0.3. Shares are of everyone the survey counts, in the Bureau’s sex-by-age table (B01001).

2 more columns on a wider screen

People in Merrimack County by age, ACS 2020–2024
Age	People	Share	New Hampshire	United States
Under 5	6,936 ±146	4.4% ±0.1	4.5% ±<0.1	5.6% ±<0.1
5 to 17	21,721 ±688	13.9% ±0.4	13.7% ±0.2	16.3% ±<0.1
18 to 24	13,967 ±812	9.0% ±0.5	8.7% ±0.2	9.1% ±<0.1
25 to 44	39,794 ±880	25.5% ±0.6	25.0% ±0.2	26.9% ±<0.1
45 to 64	42,488 ±903	27.2% ±0.6	27.9% ±0.2	24.8% ±<0.1
65 and over	31,061 ±1,021	19.9% ±0.7	20.1% ±0.2	17.2% ±<0.1

Income and poverty, 2020–2024

Median household income is $97,004 ±$2,796, and income per person $49,044 ±$1,465, in 2024 dollars. The median is $99,031 ±$1,123 in New Hampshire and $80,734 ±$166 in the United States.

Households by income

2 more columns on a wider screen

Households in Merrimack County by income, ACS 2020–2024
Household income	Households	Share	New Hampshire	United States
Under $25,000	6,217 ±601	10.2% ±1.0	10.4% ±0.3	14.6% ±<0.1
$25,000 to $49,999	8,766 ±688	14.4% ±1.1	13.4% ±0.4	16.7% ±<0.1
$50,000 to $74,999	8,703 ±620	14.3% ±1.0	14.3% ±0.4	15.5% ±<0.1
$75,000 to $99,999	7,647 ±630	12.6% ±1.0	12.4% ±0.3	12.6% ±<0.1
$100,000 to $149,999	13,214 ±858	21.7% ±1.4	20.0% ±0.5	17.5% ±<0.1
$150,000 to $199,999	7,751 ±581	12.7% ±0.9	12.7% ±0.3	9.6% ±<0.1
$200,000 or more	8,603 ±665	14.1% ±1.1	16.8% ±0.4	13.4% ±0.1

Poverty by age

The poverty rate is the share of people whose family income is below the federal threshold for their family’s size, of everyone for whom the Bureau determines it (B17020).

2 more columns on a wider screen

Poverty rate in Merrimack County by age, ACS 2020–2024
Age	Below poverty	Rate	New Hampshire	United States
All ages	11,468 ±1,262	7.6% ±0.8	7.2% ±0.3	12.5% ±0.1
Under 18	2,182 ±404	7.7% ±1.4	7.9% ±0.6	16.1% ±0.1
18 to 59	6,109 ±809	7.7% ±1.0	6.8% ±0.3	11.6% ±0.1
60 and over	3,177 ±428	7.5% ±1.0	7.7% ±0.4	11.0% ±<0.1

Housing, 2020–2024

1 more column on a wider screen

Housing in Merrimack County, ACS 2020–2024
Measure	Merrimack County	New Hampshire	United States
Housing units	66,497 ±92	648,472 ±247	143,775,355 ±10,234
Occupied	91.6% ±0.7	85.7% ±0.3	89.9% ±0.1
Vacant	8.4% ±0.7	14.3% ±0.3	10.1% ±0.1
Owner occupied	73.5% ±1.1	72.8% ±0.4	65.2% ±0.3
Renter occupied	26.5% ±1.1	27.2% ±0.4	34.8% ±0.1
Median home value	$367,600 ±$6,350	$402,500 ±$2,808	$332,700 ±$236
Median gross rent	$1,360 ±$37	$1,491 ±$15	$1,413 ±$2
Median year built	1977 ±2	1979 ±1	1980 ±1

Occupied and vacant are shares of all housing units; owner and renter occupied are shares of occupied units. Value and rent are medians in 2024 dollars.

Origin and place of birth, 2020–2024

Hispanic or Latino origin is not a race in the Census Bureau’s tables. Here the people of Hispanic origin, of any race, are one row, and everyone else is counted by race alone (B03002), so the rows add to the whole.

Hispanic origin and race

2 more columns on a wider screen

People in Merrimack County by Hispanic origin and race, ACS 2020–2024
Origin	People	Share	New Hampshire	United States
Hispanic or Latino	4,277 ±0	2.7% ±<0.1	4.7% ±<0.1	19.3% ±<0.1
White alone, not Hispanic	140,561 ±470	90.1% ±0.3	86.9% ±0.1	57.4% ±<0.1
Black alone, not Hispanic	2,471 ±354	1.6% ±0.2	1.3% ±0.1	11.9% ±<0.1
Asian alone, not Hispanic	2,358 ±320	1.5% ±0.2	2.6% ±0.1	5.9% ±<0.1
American Indian and Alaska Native alone, not Hispanic	27 to 129	< 0.1% to 0.1%	0.1% ±<0.1	0.5% ±<0.1
Native Hawaiian and Other Pacific Islander alone, not Hispanic	0 to 180	0% to 0.1%	< 0.1%	0.2% ±<0.1
Some other race alone, not Hispanic	286 to 884	0.2% to 0.6%	0.4% ±0.1	0.6% ±<0.1
Two or more races, not Hispanic	5,558 ±596	3.6% ±0.4	4.0% ±0.2	4.3% ±<0.1

A range (the estimate less and plus its margin) where the Bureau's estimate is too uncertain to state as one number: a coefficient of variation over 30%.

Place of birth and citizenship

“Born a citizen outside the states” counts people born in Puerto Rico, the island areas, or abroad to American parents. Naturalized citizens and those who are not citizens together make up the people born abroad (B05002).

2 more columns on a wider screen

People in Merrimack County by place of birth and citizenship, ACS 2020–2024
Born	People	Share	New Hampshire	United States
Born in the state	82,331 ±1,576	52.8% ±1.0	40.8% ±0.4	57.3% ±<0.1
Born in another state	65,672 ±1,511	42.1% ±1.0	51.8% ±0.4	26.9% ±<0.1
Born a citizen outside the states	1,175 ±251	0.8% ±0.2	1.3% ±0.1	1.7% ±<0.1
Born abroad	6,789 ±708	4.4% ±0.5	6.1% ±0.2	14.1% ±<0.1
Naturalized citizens	4,555 ±645	2.9% ±0.4	3.7% ±0.1	7.4% ±<0.1
Not citizens	2,234 ±476	1.4% ±0.3	2.4% ±0.1	6.8% ±<0.1

Merrimack County among the counties of New Hampshire

3rd of 10 by population, July 2025. Every one is listed on the New Hampshire page.

Counties of New Hampshire near Merrimack County in population, July 2025
County	July 2025	Change since 2020
Hillsborough County	433,415	+2.5%
Rockingham County	324,077	+3.0%
Merrimack County	158,078	+2.6%
Strafford County	135,043	+3.0%
Grafton County	93,225	+2.2%
Cheshire County	78,269	+2.3%
Belknap County	65,147	+2.1%
Carroll County	52,784	+5.0%

Elsewhere on the site

Rankings this appears in

Sources

Census Bureau population estimates — counties and Puerto Rico municipios, with components of change — U.S. Census Bureau · U.S. Government work · retrieved September 25, 2026
American Community Survey 5-year estimates — table-based Summary File · U.S. Government work

Compiled automatically from Census Bureau population estimates — counties and Puerto Rico municipios, with components of change and American Community Survey 5-year estimates — table-based Summary File by a checked SQL query · Editor: Kian O'Connor · How this site is built

Data retrieved September 25, 2026