Thousands can be constituted-of-or-filled-with square miles.
Some square feet can be constituted-of-or-filled-with (floor space).
Some square kilometers can be constituted-of-or-filled-with territory.
A (land area) can be constituted-of-or-filled-with some square kilometers.
An area can be constituted-of-or-filled-with some square feet.
Some square meters can be constituted-of-or-filled-with land.
An area can be constituted-of-or-filled-with some square km.