Gratiot Military Prison
| Location | St. Louis, Missouri |
|---|---|
| Coordinates | 38°37′12.7″N 90°11′49.9″W / 38.620194°N 90.197194°W |
| Status | Demolished (1878) |
| Capacity | 1,200 |
| Opened | 1861 |
| Closed | 1865 |
| Managed by | United States Army |
| City | St. Louis |
| State/province | MO |
| Country | USA |
| Notable prisoners | |
| M. Jeff Thompson | |
The Gratiot Military Prison, commonly known as the Gratiot Street Prison, was a military prison located in St. Louis, and the largest in Missouri at the time.