Missouri Key is a small island in the lower Florida Keys.[1]
 Satellite image of Ohio Key, Missouri Key, Little Duck Key of Lower Florida Keys | |
  Missouri Key Missouri Key  Missouri Key Missouri Key (Caribbean) | |
| Geography | |
|---|---|
| Location | Gulf of Mexico |
| Coordinates | 24°40′41″N 81°14′17″W / 24.678°N 81.238°W |
| Archipelago | Florida Keys |
| Adjacent to | Florida Straits |
| Administration | |
| State | Florida |
| County | Monroe |
U.S. 1 (or the Overseas Highway) crosses the key at approximately mile marker 39.5, between Ohio Key and Little Duck Key.
The island was named during Henry Flagler's Overseas Railroad construction years by workers from that state.
It is sometimes known locally as Little Grassy Key or Grassy Island.