SH 17 is officially split into two parts by a stretch of concurrence with US 285. The first part of the route begins in the south at the New Mexico state line where the road becomes New Mexico State Road 17. From the state line the road proceeds in a winding, generally easterly path over the San Juan Mountains via Cumbres Pass and La Manga Pass, both over in elevation. Along this section, the road offers access to Rio Grande National Forest and the many recreational activities it offers. After leaving the national forest, the road continues east for approximately 13 more miles before merging with US 285 at Antonito. From Antonito, SH 17 runs northward concurrent with US 285 for just over thirty miles to the city of Alamosa. At Alamosa, the second part of SH 17 begins after the road splits from US 285. From there, the road proceeds northward up the middle of the San Luis Valley between the Sangre de Christo Mountains in the east and the San Juan Mountains to the west. The route passes through the towns of Mosca, Hooper (where the road meets the eastern end of SH 112) and Moffat before reaching its northern terminus where it again meets US 285 roughly five miles south of Villa Grove.