It runs from the Oklahoma state line 6 miles (9.7 km) east of Follett to US 287 in Stratford.

The route was renumbered to correspond to the connecting Oklahoma State Highway 15.

[2] From 1917 the routing mostly followed present day U.S. Highway 80 from Dallas to Wills Point.

It continued on, routed along present day SH 64 from Wills Point into Tyler and up U.S. Highway 271 into Gladewater, and east along US 80 into Longview.

On January 21, 1919, an alternate route of SH 15 was designated east of Wills Point, going through Mineola to Gladewater, via US 80.

[10] On September 26, 1939, the section of SH 15 east of Albany was deleted (already part of US 80 and US 80 Alternate).