The highway's western terminus is at NM 80 north of Rodeo, in the San Simon Valley close to the border with Arizona.

A few miles east of Animas, the road again climbs and crosses the Continental Divide the first of three times, then intersects with NM 113 (which goes northbound to I-10).

Continuing east, the road crosses the Continental Divide twice in less than 2 miles (3 km), then descends to the Hachita Valley.

East of Columbus, NM 9 stays within 3 miles (4.8 km) of the Mexican border.

NM 9 officially ends at the Dona Ana County line, but the road continues as Dona Ana County Road A003 to the Pete Domenici Highway (NM 136) just west of El Paso.