Zip Code Types

The US Zip Code System is made up of four different zip code types, each playing a vital role in the US Postal Service.

Unique/Single High-Volume Address

Some ZIP codes are designated for specific locations with extremely high mail volume, often corresponding to large institutions or businesses. These unique or single high-volume address ZIP codes are typically associated with entities such as government agencies, major corporations, or large institutions that generate a significant amount of mail. They serve to streamline mail processing and delivery for these high-volume locations. Examples might include the headquarters of major companies, government offices, or institutions with extensive communication needs.

Post Office Boxes (PO Boxes)

Certain ZIP codes are designated specifically for post office boxes (PO Boxes). These ZIP codes are associated with post offices that offer the service of renting out mailboxes to individuals or businesses who prefer a secure and centralized location to receive their mail. These ZIP codes are used exclusively for PO Boxes and do not represent specific geographic areas. Individuals or businesses renting a PO Box at a particular post office will use the corresponding PO Box ZIP code when providing their mailing address.

Military Zip Codes

ZIP codes assigned to military installations or addresses associated with the U.S. military are designated as military ZIP codes. These codes are used to facilitate the delivery of mail to military bases, installations, and other addresses associated with the armed forces. Military ZIP codes may be located within the United States or overseas at international military bases. They play a crucial role in ensuring that mail and packages are efficiently delivered to service members and their families, whether stationed domestically or abroad.

Standard Zip Codes

The majority of ZIP codes fall into the category of standard codes, representing general geographic areas across the United States. These codes cover a wide range of locations, including residential areas, commercial districts, and rural communities. Standard ZIP codes are used for delivering mail and packages to a variety of addresses, from individual homes and businesses to community centers and government offices. They form the backbone of the ZIP code system, supporting the efficient sorting and delivery of mail by the US Postal Service.