Situated east of the Imperial Valley agricultural region, the dunes are bordered to the west by the Coachella Canal, a waterway diverting Colorado River water to fertile agricultural lands further north. A major east-west route of the Union Pacific railroad skirts its eastern edge, a time-worn testament to the impediment the dunes once played to travel between San Diego and Phoenix.
The dune system consists of three areas. The northernmost area is known as Mammoth Wash. This open area allows OHV use and offers a more isolated experience.
South of Mammoth Wash is the North Algodones Dunes Wilderness. Established in 1994, this area is closed to all mechanized traffic, so access is by foot or on horseback only. Here you will find endless miles of quiet solitude.
The southernmost boundary of the wilderness is State Highway 78; just south of this highway the largest and most heavily used dunes are found. With some restrictions, these primary dunes may be traveled south toward the Mexican border.