Route 80 starts at Carver Road (formerly U.S. Route 44) in the West Plymouth section of Plymouth. Due to the removal of Route 44, this is an unusual instance that a numbered route does not have its terminus with another numbered route. Though signed East, Route 80 heads "west" in the Plymouth section, and then generally north and northwest after crossing the town line into Kingston, all for the first , and is a state highway, before finally turning east at Elm Street and becoming a town-maintained road.