Juan Alonso, Mayagüez, Puerto Rico
Juan Alonso is a barrio in the municipality of Mayagüez, Puerto Rico. Its population in 2010 was 1,158. History. Puerto Rico was ceded by Spain in the aftermath of the Spanish–American War under the terms of the Treaty of Paris of 1898 and became an unincorporated territory of the United States. In 1899, the United States Department of War conducted a census of Puerto Rico finding that the population of Juan Alonso barrio was 1,041.