Route 80 is a 6.56-mile-long (10.56 km) C-shaped state highway in southeastern Massachusetts.

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 4.1 miles (6.6 km), and is a state highway, before finally turning east at Elm Street and becoming a town-maintained road.

The state highway portion of the road is also concurrent with the Claire Saltonstall Bikeway which runs for 135 miles between Boston and Cape Cod.

Parting Ways Cemetery, a 94-acre (380,000 m2) site containing the burial grounds of four former slaves who fought in the American Revolutionary War and their families, is on this highway in Plymouth, near the Kingston town line.

Sacred Heart School and Camp Mishannock, a summer camp for girls along Lake Providence, are on the Kingston portion of this highway.