
Allenstown
- County:
- Merrimack County
- County Seat:
- No
- Area (mi²):
- 20.463
- State:
- New Hampshire
Allenstown is located in Merrimack County, New Hampshire. Allenstown has a 2025 population of 4,745. Allenstown is currently declining at a rate of -0.11% annually but its population has increased by 0.7% since the most recent census, which recorded a population of 4,712 in 2020.
The average household income in Allenstown is $85,266 with a poverty rate of 12.23%. The median age in Allenstown is 36.6 years: 36.7 years for males, and 36.6 years for females.