FJNHS - 4
| Coordinates: | N 24.62795° W 82.874433° |
| Location: | Florida
Monroe County Dry Tortugas Quad |
| Elevation: | Unknown |
| Type: | Survey Mark |
| Setting: | Concrete Seawall |
| Monumented: | 1978 |
| Monumented By: | Army Corps of Engineers |
| Status: | Recovered |
| Condition: | Fair as of February 22, 2014 |
- Official Army Corps of Engineers Description: Unavailable.
This Army Corps of Engineers disk is set in the top of the concrete walkway around the moat on the western side of Fort Jefferson. It is just slightly north of the similar disk FJNHS - 5. This disk is damaged, with a chunk taken out of one side, but it still looks relatively stable and the designation is clearly legible.
