State Route 231 (SR 231) is a 11.51-mile-long (18.52 km) state highway located in Cumberland County in southeastern Maine.

The highway functions as an eastern bypass of Gray.

SR 231 proceeds north thRough the town center and crosses the Royal River.

The highway nicks the eastern corner of Gray and crosses into the town of New Gloucester, where it continues north through the town center and terminates at Lewiston Road, which carries US 202 / SR 4 / SR 100.

[2] The entire route is in Cumberland County.