The first territory the United States acquired beyond the borders of its 48 contiguous states was Alaska. Guam. Hawaii. the Philippines.

Alaska

The first territory the United States acquired beyond the borders of its 48 contiguous states was Alaska.

Explanation:

The purchase of Alaska was an acquisition of 600,000 square miles of the current state of Alaska by the United States to the Russian Empire carried out in 1867, at the request of US Secretary of State William H. Seward. It costed 7 million dollars. At the time, the transaction was considered absurd and was referred to as "Seward's folly", since it was considered to be a territory without any type of value.

In turn, Guam and the Philippines were acquired in 1898 as a result of the Spanish-American War, and Hawaii was annexed on July of that same year.