[1] One segment of 21.2 miles (34.1 km) runs from the Louisiana state line north to U.S. Route 82 (US 82) in El Dorado.

[2] A second segment of 18.12 miles (29.16 km) runs from US 79B west of Altheimer north to US 165 in England.

A third segment of 16.33 miles (26.28 km) runs from US 165 in Keo north to Highway 89 in Furlow.

[2] The route begins at US 79B west of Altheimer and runs north, intersecting Highway 31 in Sherrill near the Sherrill Methodist Episcopal Church and the Tucker School in Tucker before entering Lonoke County, where it terminates at US 165 in England.

Highway 15 continued east from El Dorado into Bradley County through Hermitage and Warren.