Delaware 15 zigzags northward from Wyoming through the west side of Dover along a combination of local roads and arterials as part of its 57-mile 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. The 2017-completed 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 Delaware 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 Turnpike at the interchange north of Dover Downs. Delaware 15 was slightly realigned with the addition of Scarborough Road so that McKee Road met it at a T-intersection.
McKee Road takes Delaware 15 northwest to Dennys Road, where the state route dog legs west to reach Kenton Road north. Kenton Road continues Delaware 15 to an overlap with Delaware 42 west to Seven Hickories.
Prior to 1990, Delaware 15 ended at U.S. 13 (Dupont Highway) by the Canterbury community. It was extended north to Middletown, then ultimately Summit Bridge by 1993.