A Yarmouth section of Route 115 (Main Street), looking west toward the U.S. Route 1 overpass
The eastern terminus of Route 115, in Yarmouth, is visible under the I-295 overpass
Route 115 serves as the primary entrance to North Windham village from the east. Within North Windham, it crosses a bridge over Ditch Brook marking the location of a terminal moraine formerly containing Little Sebago Lake until destroyed by a flood on 4 June 1814. Route 115 becomes concurrent with U.S. Route 202 at the Gray town line and parallels the west bank of the Pleasant River through West Gray until reaching Gray village after a bridge over the Maine Turnpike. Route 115 separates from Route 202 as the easterly road of the 5-way intersection at Gray village and proceeds southeasterly paralleling the west bank of the Royal River through Walnut Hill in North Yarmouth, where it is known as the Gray Road. Route 115 is known as West Main Street as it enters the town of Yarmouth, crossing the Maine Central RailroadBack Road and Lower Road a short distance northeast of their separation at Royal Junction.