Completely public, this unit is the western half of the Cabeza Prieta National Wildlife Refuge along the Mexican border and is nearly all wilderness. Only desert bighorn sheep are hunted here. Backpack or horseback hunting is recommended. Illegal immigrants and drug traffickers often steal items left at campsites.

More sheep live in here than in Unit 46A. Be ready and in shape to hike in hot weather. Pronghorn antelope and mule deer also live in here but are protected. Be prepared to encounter drug traffickers and illegal immigrants.

Large, flat expanses of desert are broken by steep mountain ranges.

Cactus and desert scrub cover much of the unit. The chief plant on the desert floor is creosote bursage. Sloping hillsides support creosote bushes, white bursage, mesquite, palo verde, ironwood, ocotillo and cacti, including cholla and saguaro.

All of Unit 46B is in Cabeza Prieta National Wildlife Refuge. Most of the refuge is designated wilderness. All vehicles must stay on El Camino del Diablo (The Road of the Devil), Christmas Pass Road and Charlie Bell Road. No bicycles or motor vehicles are allowed in the wilderness area. Hunters need four-wheel-drive vehicles with high clearance on El Camino del Diablo and Christmas Pass Roads. Two-wheel-drive vehicles with high clearance can handle Charlie Bell Road.

Most hunters camp along dirt roads. Refuge officials have designated some campsites. Lodging is in Ajo, Gila Bend and Wellton.