Portillo is a rural barrio in the municipality of Adjuntas, Puerto Rico. Its population in 2010 was 606.
Portillo was in Spain's gazetteers until Puerto Rico was ceded by Spain in the aftermath of the SpanishâÂÂAmerican 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 Portillo barrio was 1,271.