Route 156 is a Connecticut state highway running from East Haddam to Waterford.

Although much of the route follows a north-south trajectory, the entire road is signed east-west.

[1] The section of Route 156 in East Haddam and Lyme is designated as a scenic road.

[1] In 1922, a loop route of the Boston Post Road (New England Route 1) serving the coastal settlements of the towns of Old Lyme, East Lyme, and Waterford was designated as State Highway 333.

At the same time, the road serving the village of Hamburg in the town of Lyme on the east side of the Connecticut River was designated as State Highway 150.