Río Abajo is a barrio in the municipality of Utuado, Puerto Rico.

Río Abajo was in Spain's gazetteers[6] until 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 Río Abajo barrio was 1,235.

[7] Hurricane Maria which struck Puerto Rico on September 20, 2017, washed away the Río Abajo bridge and approximately 60 families were left isolated.

Residents invented a zip line to bring food across until a temporary bridge was built.