The historic U.S. Route 66 ran east–west across the central part of the state of New Mexico, along the path now taken by Interstate 40. However, until 1937, it took a longer route via Los Lunas, Albuquerque, and Santa Fe, now roughly New Mexico State Road 6, I-25, and US 84. Large portions of the old road parallel to I-40 have been designated NM 117, NM 118, NM 122, NM 124, NM 333, three separate loops of I-40 Business, and state-maintained frontage roads.
It is one of the roads on the Trails of the Ancients Byway, one of the designated New Mexico Scenic Byways.