Map of Litchfield County in northwestern Connecticut with Route 109 highlighted in red
|Maintained by ConnDOT|
|Length||20.93 mi (33.68 km)|
|West end||US 202 in New Milford|
|East end||US 6 / Route 254 in Thomaston|
Route 109 begins at an intersection with US 202 in New Milford and heads northeast into Washington, where if overlaps Route 47 for 0.28 miles (0.45 km) before continuing into Morris. In Morris, Route 109 heads east, then northeast and southeast, before cutting across a corner of Litchfield by the Wigwam Reservoir into Thomaston. In Thomaston, Route 109 continues southeast and then east along the Wigwam Reservoir and Branch River to end at an intersection with US 6 and Route 254.
In 1922, the Bantam to Morris route was designated as State Highway 310. This became part of Route 109 when it was commissioned in 1932, running from the Bantam section of Litchfield past Bantam Lake to its current eastern terminus in Thomaston. In 1963, the section past Bantam Lake was reassigned to Route 209 and Route 109 was rerouted to its current western terminus using former SR 857. In 1968, the section near the Branch River in Thomaston was rerouted uphill to accommodate a flood control project.
The entire route is in Litchfield County.
|New Milford||0.00||0.00||US 202 – Brookfield, Litchfield|
|Washington||6.10||9.82||Route 47 north – New Preston||Northern terminus of CT 47 overlap|
|6.38||10.27||Route 47 south – Woodbury||Southern terminus of CT 47 overlap|
|Morris||12.45||20.04||Route 209 north – Bantam|
|14.06||22.63||Route 61 – Litchfield, Bethlehem|
|15.20||24.46||Route 63 – Litchfield, Watertown|
|Thomaston||20.93||33.68||US 6 to Route 254 / Route 8 – Plymouth, Watertown, Northfield, Torrington|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi|
- "Road Conditions in Connecticut". The Hartford Daily Courant. May 27, 1932. p. 14. Retrieved December 24, 2019 – via Newspapers.com.
- Connecticut State Highway Log Archived 2015-07-26 at WebCite
- ConnDOT map of Thomaston
- "Road Conditions in Connecticut". The Hartford Daily Courant. April 23, 1932. p. 19. Retrieved December 24, 2019 – via Newspapers.com.
- Connecticut Routes, Route 109