What was the cost of the Louisiana Purchase per square mile?
$18 per square mile
A square mile is an area measurement, not a specific shape. They could be just about anything, as long as they multiply together to make one square mile. 1 mile by 1 mile is a square mile. Two miles by half a mile is a square mile. 1 foot by 5280 miles is a square mile. This means that 8 square miles can be 2 miles by 4 miles or 1 mile by 8 miles.