SR 112 begins in downtown Saco at the intersection of Main and Beach Streets.

Near West Buxton, SR 112 begins to closely parallel the Saco River and turn to the north.

The two routes head southeast towards Gorham Center for about 1.7 miles (2.7 km) before reaching a roundabout.

The SR 112 expressway resumes heading south through wetlands without any cross roads.

The road curves to the east before it ends at a roundabout with SR 114 southeast of Gorham Center.