San Bernardino County, California
Increase (July 2005 - July 2006): 34,821
The largest county in terms of area in the United States, San Bernardino encompasses more acreage than the states of Massachusetts, Connecticut, Delaware and Rhode Island combined!
Like its next-door neighbor to the south, Riverside County, the western reaches of San Bernardino County have become bedroom communities for many workers from Los Angeles seeking affordable housing.
Much of the county is still undeveloped and boasts wide areas of mountain and desert wilderness. That includes Death Valley National Park.