a) Kalawao County, Hawaii. According to the U.S. Census Bureau, the county has a total area of 53 square miles (140 km2), of which 12 square miles (31 km2) is land and 41 square miles (110 km2) (77.3%) is water. By land area, it is the smallest county in the United States.
b) Loving County is a county in the U.S. state of Texas. As of the 2010 census, the population was 82, making it the least populous county in the United States.