Postal codes in Puerto Rico, a United States commonwealth, are part of the United States ZIP code system.
Both Puerto Rico and the U.S. Virgin Islands are served from the sectional center facility (SCF) of San Juan, Puerto Rico.
[1] ZIP codes in the 006xx range are used in northwestern Puerto Rico; 007xx in southeast Puerto Rico; and 009xx in the San Juan Metropolitan Area.
As in the rest of the United States, the fourth and fifth digits designate a post office or town; or in densely populated areas, an area or borough of a city.
Originally, the ZIP codes were arranged in consecutive alphabetical order, with the 006xx range covering the offices from A to L, and the 007xx range covering the offices from M to Z.