San Bernardino County is a county in the U.S. state of California. In the 2010 census, the population was 2,035,210, up from 1,709,434 in the 2000 census. With an area of 20,105 square miles, San Bernardino County is the largest county in the United States by area (Alaska has boroughs). It is larger than each of the nine smallest states, larger than the four smallest states combined, and larger than the nations of Bosnia and Herzegovina and Costa Rica.