New Hampshire Population By County in 2021 (ACS-5Yrs)

Based on the US Census ACS-5Yrs estimates, in 2021, the total population of New Hampshire was 1.37M. Among all New Hampshire counties, Hillsborough was the most populated county (420.50K), followed by Rockingham (312.77K), and then Merrimack (152.98K).

On the other hand, the least populated counties were: Coos (31.36K), Sullivan (43.11K), and Carroll (49.96K).

The chart and table below shows the population of each county and the percentage of New Hampshire population in each county.

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