The University of California Natural Reserve System (UCNRS) is a system of protected areas throughout California. The reserves support UC's mission of teaching, research, and public service. Unlike national and state parks, they are not available for recreational uses, because they were specifically created to enable UC scientists to conduct research free from such distractions.

The Donald and Sylvia McLaughlin Natural Reserve is a 7,050-acre (28.5 km2) University of California Natural Reserve System reserve in the Blue Ridge Berryessa Natural Area, in Napa and Lake counties of California. The site is owned by the Homestake Mining Company, and is the site of the now-closed McLaughlin Mine.