| State: | ME |
| Type: | SR |
| Route: | 186 |
| Map Custom: | yes |
| Length Mi: | 16.00 |
| Length Ref: | [1] |
| Established: | 1925 |
| Direction A: | West |
| Direction B: | East |
| Terminus A: | in Gouldsboro |
| Junction: | in Gouldsboro |
| Terminus B: | in Gouldsboro |
| Counties: | Hancock |
| Previous Type: | SR |
| Previous Route: | 185 |
| Next Type: | SR |
| Next Route: | 187 |
State Route 186 (SR 186) is a 16miles state highway in south central Maine. The highway serves the town of Gouldsboro, running in a half-loop from U.S. Route 1 (US 1), south and east along the southern coast to Winter Harbor near Frenchman Bay, and then returning to US 1.