County statistics of the United States

Note that the only entity on this list with a permanent human population is Swains Island, American Samoa.

The first 8 counties (county-equivalents) are uninhabited, while the 10th on the list (Palmyra Atoll) has a small non-permanent human population whose maximum capacity is 20 people.

[8] If the U.S. territories are included, the smallest county-equivalent is Kingman Reef, with a land area of 0.012 square miles (3.1 ha; 7.7 acres).

Though not on the list, the North Slope Borough is the largest independently incorporated county equivalent.

The Unorganized Borough is substantially larger, but is an extension of the State of Alaska government and not independently incorporated.

[A] Also note that the smallest land area with county-level governance in the U.S. is Falls Church, Virginia, but it is an independent city and not a county or part of one.

The list is dominated by just a few states: Alaska, Montana, and Texas together comprise about two-thirds of the entries.

If the census areas were removed from the list, the Unorganized Borough would rank fourteenth with a density of 0.38 per square mile (0.15/km2).

Excluding the census areas of Alaska, Lake and Peninsula Borough is the least densely populated county equivalent with 0.069/sq mi (0.027/km2).