The entire world's population of the California Gnatcatcher occurs in Baja California and coastal southern California year-round where it depends on a variety of arid scrub habitats. Limited to coastal sage scrub habitat in California and northern Baja but more widespread in southern Baja. Even in the early 1900's, the population was described as being scarce and irregularly distributed but by the 1940's habitat was noticeably reduced. In the U.S. loss of coastal sage scrub habitat has been estimated to be as much as 70-90%, with approximately 33% lost since 1993 when the species was Federally-listed as Threatened.