Merrimack County Flag

Merrimack County

State:
New Hampshire
County Seat:

Merrimack County's estimated 2026 population is 159,489 with a growth rate of 0.51% 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 8.94% since that time.

159,489
Total Population
171
Population Density (mi²)
3
Population Rank (State)
810 0.51%
Annual Population Growth

Merrimack County Population

Demographics

Economics and Income Statistics