- Length 51.0 miles; 19.06 miles in Connecticut
- From Route 4 in Torrington
- To US 7/20 in Lenox, Mass.
In Connecticut, Route 183 follows a Maine-style "concurrency for the sake of it" through Winsted along Route 8 (0.33 mile) and US 44 (2.14 miles). It looks like two separate roads, west and east of Route 8, arbitrarily stitched together.
Massachusetts is where Route 183 really gets strange.
Across the state line, MA 183 shoots north-northwest into New Marlborough, where it continues as a moderately-marked overlap with MA 57. North of Lake Buell, at MA 23, MA 57 comes to an end; but MA 183 continues as an overlap with MA 23. In Great Barrington, MA 183 disappears from signs, but continues as a hidden overlap with US 7, before finally striking out on its own toward Stockbridge and Lenox.
CT 183 History
In the 1920s, today's Route 183 from Winsted to Colebrook was represented by state highways 174 and 314, funded as a state aid road: improvements were partially funded by the towns. In 1926, a Colebrook lawmaker succeeded in having the road become a trunk line route to the Massachusetts state line; both states proceeded to improve the route as a third road through the Berkshire mountains. The improved access led to a small real estate boom along the road.
Today's Route 183 was commissioned as an 8.75-mile route in 1932, from US 44 in Winchester to the state line. The Torringford Street segment, east of Route 8, was originally locally maintained, before becoming an unsigned state route (SR 710) in 1943.
In 1954, Route 183 was extended south along US 44 and SR 710 to today's Route 4; this might have been done at the same time Route 72 was extended in the area, on May 1, 1954.
In 1959, the Route 183 corridor was considered by Massachusetts officials as a new location for a relocated Route 8, which would be displaced by a planned dam in Colebrook.
The original stone-and-mortar Colebrook Bridge over Center Brook, dating back to 1784, was widened in the late 1980s. Instead of discarding the old stonework, they took it apart and replaced it on the outside of the new structure. This idea earned the state DOT an Award of Merit in Historic Preservation And/Or Cultural Enhancement in 1990.