This is a list of the 100 largest counties in the United States by area.
The list is based upon the total area of a county, both land and water surface, reported by the United States Census Bureau during the 2000 Census.
Some counties, such as Keweenaw and Alger Counties in Michigan, include significant amounts of water in their total area and would not appear on a list that considered land area alone.
Nine US states are smaller than San Bernardino County, California, and two states, Rhode Island and Delaware are smaller than the smallest counties on this list.
With an area of 323,440 sq mi (837,700 km2), it would easily top the list, outranking every state in the country (except Alaska).