NM 81 begins at the Mexico – U.S. border crossing in Antelope Wells, Hidalgo County; a local road links the crossing with Mexico Federal Highway 2 to the south. The border crossing in Antelope Wells is the least-trafficked crossing between Mexico and the U.S., and the only residents of Antelope Wells are U.S. Customs and Border Protection employees.[2] North of Antelope Wells, the road passes through desert terrain, with a mountain range to the west. The road does not pass any communities or service stations between Antelope Wells and Hachita, and it has been described as "quiet" and "isolated"; according to NMDOT, 129 vehicles travel the road per day.[2][3] Continuing north, the road enters a semi-arid farming region and passes another mountain range in the east. The road makes a turn to the north-northeast and crosses into Grant County before terminating at NM 9 in Hachita.[1][4]
