Waltham
- County:
- Mower County
- County Seat:
- No
- Area (mi²):
- 0.478
- State:
- Minnesota
Waltham is a city located in Mower County, Minnesota. Waltham has a 2026 population of 167. Waltham is currently growing at a rate of 1.21% annually and its population has increased by 1.21% since the most recent census, which recorded a population of 165 in 2020.