The U.S. Fish and Wildlife Service (Service) designated 2,485 acres in Kern County and Kings County in California as critical habitat for the Buena Vista Lake shrew (Sorex ornatus relictus).  The Buena Vista Lake shrew is a small, insect-eating mammal native to the southern San Joaquin Valley.

In 2005, the Service issued a final rule designating just 84 acres as critical habitat.  That rule was challenged, and the Service settled the lawsuit and initiated a new rulemaking.  Pursuant to that rulemaking process, in 2012 the Service issued a proposed rule designating 5,182 acres as critical habitat.  The Service reduced the area designated by 2,687 acres as a result of implementation of a habitat management plan by the City of Bakersfield and an additional 10 acres due to adjustment to mapping boundaries.