The Ballajá Barracks (Cuartel de Ballajá in Spanish) is a historic building and former military barracks located in the Ballajá section of Old San Juan, in the city of San Juan, Puerto Rico. It is located close to El Morro and its esplanade, between the Morovis, Beneficiencia and streets. It was built from 1854 to 1864 to house Spanish and Puerto Rican regiments. The Ballajá Barracks were the last large-scale construction project made by the Spanish Crown in the Americas.