By plane
There has been commuter-airline service to Gallup, the next significant town west of Grants on I-40, but there is none as of December 2005. The nearest major airport is in Albuquerque, about 90 miles 150 km away and only slightly farther from El Malpais than Gallup is. Since you're going to need to rent a car or SUV anyway if you fly, might as well get it in Albuquerque and drive, even if the commuter service resumes; it'll be quicker than flying into Gallup and driving back east. From the Albuquerque airport, drive north on Interstate 25 to Interstate 40 and continue as above.
By car
El Malpais is located south of the town of Grants. Two major state highways border the monument and conservation area and both are accessed via Interstate 40. Exit 89, east of Grants, will take you along NM 117 which forms the eastern park boundary. BLM's El Malpais Ranger Station is located 9 miles south of this exit and is open daily. Exit 85 at Grants will take you to the Northwest New Mexico Visitor Center, a multi-agency facility, located south of exit 85. Exit 81, west of Grants, will take you along NM 53 which forms the northwestern park boundary. NPS's El Malpais Information Center is located 23 miles south of this exit and is open daily.