Merrimack County Flag

Merrimack County

State:
New Hampshire
County Seat:

Merrimack County's estimated 2025 population is 158,391 with a growth rate of 0.41% in the past year according to the most recent United States census data. Merrimack County is the 3rd largest county in New Hampshire. The 2010 population was 146,395 and has seen a growth of 8.19% since that time.

158,391
Total Population
170
Population Density (mi²)
3
Population Rank (State)
644 0.41%
Annual Population Growth

Merrimack County Population

Demographics

Economics and Income Statistics