San Luis
- County:
- Costilla County
- County Seat:
- Yes
- Area (mi²):
- 0.567
- State:
- Colorado
San Luis is a town located in Costilla County, Colorado. San Luis has a 2026 population of 628. It is also the county seat of Costilla County. San Luis is currently growing at a rate of 1.62% annually and its population has increased by 4.67% since the most recent census, which recorded a population of 600 in 2020.