SR 15 zigzags northward from Wyoming through the west side of Dover along a combination of local roads and arterials as part of a 57 mile long route north from the Milford area to Summit Bridge. SR 15 follows Dundee Road north from SR 10 Alt to SR 10, and Moose Lodge Road through open farm land and along the west boundary of Wyoming. The route dog legs east along Southern Boulvard to Railroad Avenue and Wyoming Mill Road north through Wyoming.
Wyoming Mill Road extends SR 15 north into southwest Dover. Completed in 2017, POW/MIA Parkway ties into the state route along this stretch. Built as part of the West Dover Connector, the boulevard system includes connections to U.S. 13 at Rodney Village and at the turn of SR 15 onto Saulsbury Road north from North Street east.
Saulsbury Road heads north through industrial areas of Dover to become Mckee Road ahead of Scarborough Road. Scarborough Road was constructed as a belt route to connect west Dover with the SR 1 toll road at the interchange north of Dover Downs. SR 15 was slightly realigned with the addition of Scarborough Road so that McKee Road met it at a T-intersection.
McKee Road takes SR 15 northwest to Dennys Road, where the state route dog legs west to reach Kenton Road north. Kenton Road continues SR 15 to an overlap with SR 42 west to Seven Hickories.
Prior to 1990, SR 15 ended at U.S. 13 (Dupont Highway) by the Canterbury community. It was extended north to Middletown, then ultimately Summit Bridge by 1993.