The Pacific pocket mouse is one of 16 currently recognized subspecies of the little pocket mouse that is widely distributed throughout arid regions of the western United States, extending into the northern part of the Baja California peninsula and west central Sonora, Mexico. Historically, the Pacific pocket mouse was found within 2.5 miles of the Pacific Ocean in Los Angeles County south to the vicinity of the Mexican border in San Diego County, California. After 20 years with no reports of the species remaining in existence, a single population was discovered in coastal Orange County, California, leading to emergency listing of the subspecies as endangered in 1994. Since listing, three additional populations have been found within Marine Corps Base Camp Pendleton in north San Diego County. The Pacific pocket mouse is primarily associated with sandy soils in a range of habitats with open vegetation structure structure
Something temporarily or permanently constructed, built, or placed; and constructed of natural or manufactured parts including, but not limited to, a building, shed, cabin, porch, bridge, walkway, stair steps, sign, landing, platform, dock, rack, fence, telecommunication device, antennae, fish cleaning table, satellite dish/mount, or well head.

Learn more about structure  in coastal southern California, including dunes, strands, mesas and drainages with mixed coastal scrub, grasses and forbs.  All known populations are threatened by habitat fragmentation and degradation and small population size.