Fort Mason Tunnel
| The west portal of the Fort Mason Tunnel in disuse as seen in June 2017 | |
| Overview | |
|---|---|
| Line | State Belt Railroad | 
| Location | San Francisco, California | 
| Coordinates | 37°48′19″N 122°25′52″W / 37.8054°N 122.43118°W | 
| Start | Van Ness | 
| End | Marina Bl. at Laguna St. | 
| Operation | |
| Opened | 1914 | 
| Closed | 1993 | 
| Owner | National Park Service | 
| Character | Tunnel | 
| Technical | |
| No. of tracks | 1 | 
| Track gauge | 4 ft 8+1⁄2 in (1,435 mm) standard gauge | 
Fort Mason Tunnel is an abandoned single-track railway tunnel in San Francisco which runs under a small hill upon which sits a portion of the old Fort Mason. The tunnel was constructed in 1913 and opened to rail traffic in 1914. The east portal is near the north end of Van Ness Avenue; the west portal feeds onto Marina Boulevard at Laguna Street.