After downtown, the two routes meander to the northwest as a two-lane rural road through Berkshire County, reaching the village of Hartsville.

Now on the western shore of the river, Route 183 runs north along the riverside on Front Street along tracks owned by the Housatonic Railroad.

A short distance north, the route crosses under the Mass Pike (I-90) and enters the community of Interlaken.

Route 183 wanders north through Stockbridge before entering the town of Lenox, where it gains the name of West Street.

Route 183 continues east along Walker Street out of downtown Lenox and into an intersection with US 7 and US 20, which connect to Pittsfield.