NM 198's southern terminus is at the entrance to the Spring Canyon State Park, and the northern terminus is southeast of Deming at the road's junction with NM 143, just west of the Rockhound State Park.

The road starts out by heading southeast through the arid desert, skirting the Little Florida Mountains from the west.

Continuing south the road goes over a side of Castle Rock at a 2-mile mark, makes another sharp right-to-left turn and arrives at the entrance of the Spring Canyon State Park at the mouth of the Spring Canyon in the northern part of Florida Mountains.

After Rockhound State Park was formed in 1966, a road was built connecting it to NM 11 south of Deming.

The former county roads were broken up into several segments to avoid road concurrency, with the stretch between the entrance to the Rockhound State Park and Spring Canyon State Park being designated as NM 198.