New Hampshire Population By County in 2020

Updated on June 16, 2025.

Based on the US Census Vintage data estimates, in 2020, the population of New Hampshire was 1,378,756. Among all New Hampshire counties, Hillsborough had the highest population (422,929), followed by Rockingham (314,664), and Merrimack (154,039). Coos was the least populated county (31,228).

Hover over or click on the counties in the map below to see the populations. The data can also be found in a table below. You can use the table to sort, filter, and explore the data further.

You can see similar information for other states and by state for the United States.

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New Hampshire Population By County in 2020
New Hampshire Population By County in 2020
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County Population % of State Population
Belknap 63774 4.63
Carroll 50240 3.64
Cheshire 76542 5.55
Coos 31228 2.27
Grafton 91197 6.61
Hillsborough 422929 30.68
Merrimack 154039 11.17
Rockingham 314664 22.82
Strafford 131074 9.51
Sullivan 43069 3.12