
St Marie
- County:
- Valley County
- County Seat:
- No
- Area (mi²):
- 22.898
- State:
- Montana
St. Marie is a CDP located in Valley County, Montana. St. Marie has a 2025 population of 469. St. Marie is currently growing at a rate of 3.08% annually and its population has increased by 44.31% since the most recent census, which recorded a population of 325 in 2020.
The average household income in St. Marie is $36,824 with a poverty rate of 27.9%. The median age in St. Marie is 39.3 years: 38.3 years for males, and 40 years for females.