Route 66 in New Mexico was marked over portions of two auto trails — the National Old Trails Road from Arizona via Albuquerque and Santa Fe to just shy of Las Vegas, and one of the main routes of the Ozark Trails network from that point into Texas. The state had taken over maintenance of these roads under several numbers: NM 6 from Arizona to Los Lunas, part of NM 1 through Albuquerque and Santa Fe to near Las Vegas, NM 56 to Santa Rosa, the short NM 104 to Cuervo, and part of NM 3 to Texas. While NM 56 and NM 104 were completely absorbed by US 66, NM 6 was reassigned to a route splitting from US 66 (old NM 6) at Laguna and heading straight east through Albuquerque, Moriarty, and Palma to US 66 at Santa Rosa. Except between Albuquerque and Moriarty, where it formed part of US 470, this was an unimproved road.
The new NM 6 was approved as a future realignment of Route 66 by 1932, and in 1933, a new bridge over the Rio Puerco opened. Once paving was completed in 1937, with AASHO approval given on September 26, 1937, Route 66 was moved to this shorter route, known as the Laguna Cut-off west of Albuquerque and the Santa Rosa Cut-off east of Albuquerque. The bypassed roads became NM 6 once again to the west and part of US 84 to the east