Also Glamis Dunes, Imperial Sand Dunes Recreation Area. Roughly 72 kilometers long by 10 kilometers wide (45 miles by 6 miles). Spanish word algodones translates to the English word cotton. Chocolate Mountains in background. North Algodones Dunes Wilderness; The federal government protected the northern 25,818 acres (104 km²) in the early 1980s and closed them to vehicles as part of the 1994 California Desert Protection Act (Public Law 103-433). Imperial County, CA.