Answer:
At the time of the American Revolution, Puerto Rico was owned by Spain.
Explanation:
During the 18th century, the island of Puerto Rico belonged to the Spanish Empire. It was one of its colonies in North America and the Caribbean, along with Cuba, Florida, Mexico and other territories.
Puerto Rico remained in Spanish hands until the Spanish-American War of 1898, that faced Spain against the United States of America, that entered into the war to help Cuba gaining its independence. As a result of this war, which was won by America, Puerto Rico, Cuba, and the Philippines passed to American control.