Merrimack County, New Hampshire

Merrimack County population, land area and income

Merrimack County had 157,869 residents in the Census Vintage 2024 estimate, on 932.9 square miles of land. It ranks 3rd of 10 in New Hampshire by population and 3rd by land area. That works out to 169.2 people per square mile, 1.8 times the US average of 96.3, and in the top quarter nationally.

The median county-equivalent in New Hampshire has 85,562 residents; Merrimack County is somewhat larger.

Its SAIPE 2023 median household income of $91,357 is in the top tenth among 3,143 counties with an estimate.

How Merrimack County's population changed since 2020

Merrimack County gained 3,830 residents between the July 2020 and July 2024 estimates, a rise of 2.5%. That ranks 2nd of 10 in New Hampshire for growth. The median New Hampshire county changed by +2.3%, and the state as a whole by +2.2%.

Since the April 2020 estimates base, Merrimack County recorded 5,574 births and 6,860 deaths, a natural change of -1,286. Net international migration added +851 and net domestic migration, people moving to or from other US counties, came to +4,334. The largest single component was domestic migration, which added 4,334 people.

Where Merrimack County is

The Census internal point of Merrimack County is at 43.299600, -71.680000. It sits in UTM zone 19N. The map shades New Hampshire's 10 county-equivalents by population change from 2020 to 2024, darker for faster growth, with Merrimack County outlined. Dots are towns of 1,000+ people with residents in it.

Towns in Merrimack County

2 incorporated places of 1,000+ people have residents in Merrimack County, 53,497 people together, or 34% of the county. Each figure counts only the part of the town inside Merrimack County; towns marked "part" extend into another county. The largest is Concord with 44,674.

Counties bordering Merrimack County

The Census 2024 county adjacency file lists 6 neighbors for Merrimack County. The most populous is Hillsborough County, NH, with 430,462 residents. Distances run between Census internal points in a straight line.

• Hillsborough County

  430,462 people

  27 mi S

• Rockingham County

  322,433 people

  36 mi SE

• Strafford County

  134,202 people

  32 mi E

• Grafton County

  93,045 people

  44 mi N

• Belknap County

  65,257 people

  20 mi NE

• Sullivan County

  44,012 people

  28 mi W

Distance to Concord and the nearest big city

Concord is 9.6 miles SE of Merrimack County's internal point in a straight line. The nearest place of 100,000 or more is Manchester, NH (population 116,386), 24.8 miles away. The nearest place of 10,000 or more is Concord, NH (population 44,674), 7.6 miles away.

Merrimack County FIPS code

The FIPS code of Merrimack County is 33013: state code 33 for New Hampshire plus county code 013. Use it as text, with the leading zero, when joining Census, BLS, or CDC county tables. SAIPE lists its 2023 median household income as $91,357.