| U.S. Post Office | |
| Location: | St. Petersburg, Florida |
| Coordinates: | 27.7717°N -82.6389°W |
| Built: | 1916-1917 |
| Architect: | George W. Stewart |
| Architecture: | Classical Revival with Spanish Colonial elements |
| Added: | April 4, 1975 |
| Refnum: | 75000564 |
The U.S. Post Office (also known as the Open Air Post Office) at 400 First Avenue North in St. Petersburg, Florida is a historic building. On April 4, 1975, it was added to the U.S. National Register of Historic Places.