Route 137 begins at an intersection with Route 28 (Main Street) just east of South Chatham, within the town of Chatham. Route 137 proceeds north along Meetinghouse Road, passing a residential strip before bending northeastward. The route soon enters the community of East Harwich, crossing through some woods at the southern end. At Old Queen Anne Road, Route 137 makes a sharp turn to the northwest and enters downtown East Harwich.
