| State: | CT |
| Type: | CT |
| Route: | 309 |
| Map Custom: | yes |
| Map Notes: | Map of Hartford County in northern Connecticut with Route 309 highlighted in red |
| Length Mi: | 4.74 |
| Length Round: | 2 |
| Length Ref: | [1] |
| Established: | 1963 |
| Direction A: | West |
| Terminus A: | in Canton |
| Direction B: | East |
| Terminus B: | in Simsbury |
| Counties: | Hartford |
| Previous Type: | Route |
| Previous Route: | 305 |
| Next Type: | Route |
| Next Route: | 313 |
Route 309 is a Connecticut state highway in the northwestern Hartford suburbs running from Canton to Simsbury.
Route 309 begins at an intersection with Route 179 in North Canton and heads southeast into Simsbury. In Simsbury, it curves southeast and east to end at an intersection with Route 167.[1]
North Canton Road and West Simsbury Road was established as SR 909 in 1962 as part of the Route Reclassification Act. The following year, SR 909 became a signed route, with the designation Route 309.[2]