
Plainfield
- County:
- Hampshire County
- County Seat:
- No
- Area (mi²):
- 21.123
- State:
- Massachusetts
Plainfield is located in Hampshire County, Massachusetts. Plainfield has a 2025 population of 639. Plainfield is currently growing at a rate of 0.16% annually and its population has increased by 1.11% since the most recent census, which recorded a population of 632 in 2020.
The average household income in Plainfield is $110,669 with a poverty rate of 14.35%. The median age in Plainfield is 50.3 years: 55.5 years for males, and 47.5 years for females.