New Mexico State Road 4 (NM 4) is a 67.946-mile-long (109.348 km) state highway in Sandoval, Los Alamos, and Santa Fe counties in New Mexico, United States. It is significant as the main access route (in conjunction with NM 501 and NM 502) connecting the remote town of Los Alamos, Los Alamos National Laboratory, and Bandelier National Monument to other, more major highways in New Mexico.