After several attacks and raids from the Seminole Indians, Florida became too much handle
Explanation:
The Gadsden purchase completed the final outline of the United States in 1854 when the U.S. purchased land from Mexico that became part of the modern states of Arizona and New Mexico.
Spain reacquired Florida from the British after the American Revolution but found that holding it was a cumbersome and financially draining endeavour with constant border disputes with the U.S. and with several attacks and raids from Native Indians. They therefore 'sold' Florida to the Americans.
