The two are inconvertible. A mile is a measure of length while a square mile is a measure of area. However, 1 square mile is 1 mile x 1 mile.
There are no square miles in a mile. A square mile is a unit of area and a mile is a unit of length.
Miles measures distance. Square miles measures area. Therefore, you can not compare the two.
United States - 3,794,101 square miles.
385,252 km2 or 148,746 sq mi