US ZIP codes can be divided by 4 default types: PO Box, Unique, Military and Standard. In this article we will tell what does each of them mean.
Default types of ZIP code
Firstly, let’s see what type of ZIP code you can meet:
- PO Box.
Standard ZIP codes
Standard ZIP codes belong to usual regular addresses. It contains such addresses that receive mails and other shipments at that physical location. In other words, if the parcel can be delivered directly to somebody’s home (at the front door), its address will get “S” classification from USPS (what means “Standard” category).
All usual addresses where people live mostly meet this qualification.
Military ZIP codes
Military ZIP codes belong to American military bases, including those which are situated overseas. USPS provides them domestic mailing addresses literally everywhere (on ships at sea, in embassies and bases around the world, etc.), but due to specificity of such locations they’ve got “M” (“Military”) classification. Such approach gives an opportunity for USPS to reach this addresses but only using methods and delivery systems more similar to international shipping.
Unique ZIP codes
The “U” classification is provided to individual addresses (addresses of companies, organizations, and other institutions that receive large quantities of mail).
ZIP codes of PO Boxes
PO Box is the last representative of ZIP code default types. It has the “P” classification, the main feature of which is that mail is not delivered right to your doorstep but to the post office. USPS classifies with this label every ZIP Code that doesn’t provide service to home and business locations.