Route 41 is a 31.1588-mile-long (50.1452 km) extension of Connecticut Route 41 into Massachusetts. It begins at the Connecticut state line in Sheffield and ends at U.S. Route 20 in Pittsfield. Route 41 was the original alignment for New England Interstate Route 4 south of Great Barrington prior to 1930.

Sheffield is a town in Berkshire County, Massachusetts, United States. It is part of the Pittsfield, Massachusetts, Metropolitan Statistical Area. The population was 3,327 at the 2020 census. Sheffield is home to Berkshire School, a private preparatory school. The former resort town includes the village of Ashley Falls, and is bordered by various other towns and villages, such as Egremont and Great Barrington. Its southern border is the Massachusetts-Connecticut state line.