Dunstan is a census-designated place (CDP) in the town of Scarborough, Cumberland County, Maine, United States. Also known as West Scarborough, the community is in the southwest part of the town, along U.S. Route 1. Maine State Route 9 runs northward from Dunstan with US 1 towards Portland but leads southeastward out of the community as Pine Point Road, towards Old Orchard Beach. Interstate 95 forms the northwestern edge of the CDP, and the York County line is the southwestern border, with the city of Saco directly adjacent to Dunstan. The northeast edge of the CDP is the Dunstan River, an arm of the tidal Scarborough River.