sentences:  The least extensive county is Kalawao County, Hawaii, with a land area of 11.991 square miles (31.058 km2).The least extensive county-equivalent in the 50 states is the independent City of Falls Church, Virginia, with a land area of 1.999 square miles (5.177 km2).If U.S. territories are included, the least extensive county-equivalent is Kingman Reef, with a land area of 0.01 square miles (0.03 km2).