The United States may purchase, acquire, hold, own, occupy, and possess such lands within the limits of this state as they shall seek to occupy and hold as sites on which to erect and maintain forts, magazines, arsenals, dockyards, and other needful buildings, or any of them, as contemplated and provided in the Constitution of the United States; such land to be acquired either by contract with owners, or in the manner hereinafter provided.
Fla. Stat. § 6.02