How did the United States acquire Puerto Rico?
Peace treaty after the Hipanoamerican War of 1898, USa won over spain an in the Treaty of Paris they got from Spain Puerto Rico along with Cuba, Guam and the Philipines. However, during the war (before the Treaty) US military forces invaded PR in 25 JULY 1898. Check more info about the Hipanoamerican War of 1898 at the internet.