 This total does not include people of Puerto Rican descent who were born in the mainland of the United States.Spain officially ceded Puerto Rico to the United States under the terms of the 1898 Treaty of Paris which concluded the Spanish–American War.It is a United States territory and upon the outbreak of World War I, the Congress enacted the Jones–Shafroth Act, which gave Puerto Ricans American citizenship with certain limitations (for example, Puerto Ricans are not allowed to vote in presidential elections).