Westby
- County:
- Sheridan County
- County Seat:
- No
- Area (mi²):
- 0.562
- State:
- Montana
Westby is a town located in Sheridan County, Montana. Westby has a 2026 population of 162. Westby is currently declining at a rate of -1.22% annually and its population has decreased by -2.99% since the most recent census, which recorded a population of 167 in 2020.