US ZIP codes are a type of postal code used within the United States to help the United States Postal Service (USPS) route mail more efficiently. Some still refer to ZIP codes as US postal codes. The term ZIP stands for Zone Improvement Plan. The basic 5-digit format was first introduced in 1963 and later extended to add an additional 4 digits after a dash to form a ZIP+4 code. The additional 4 digits help USPS more precisely group mail for delivery.

Though ZIP codes were originally developed for USPS, many other shipping companies such as United Parcel Service (UPS), Federal Express (FedEx), DHL, and others make use of ZIP codes for sorting packages and calculating the time and cost of shipping a package (the shipping rate). Types of Zip Codes • Unique/single high volume address (ex. 20505 for the CIA in Washington, DC) • PO Box only (ex. 22313 for the PO Boxes of Alexandria, VA) • Military • Standard (all other ZIP codes) Assignment of ZIP codes and Mail Sorting. The first digit of a USA ZIP code generally represents a group of U.S. The map of the first digit of above shows they are assigned in order from the north east to the west coast. The first 3 digits of a ZIP code determine the central mail processing facility, also called sectional center facility or 'sec center', that is used to process and sort mail.

House village east cainta cogeo antipolo. Usually, more than one code is issued for areas within Metro Manila, and provincial areas are issued one code for every town and city, with some rare exceptions such as, which has three ZIP codes (4114, 4115, and 4126) and, which has. Moved Permanently. The document has moved here.

All mail with the same first 3 digits is first delivered to the same sec center where it is sorted according to the last 2 digits and distributed to local post offices. The sec centers are not open to the public and usually do most sorting overnight.

As you can see from the, the digits after the first are also generally assigned from east to west. In the map, 0 is closer to white and 9 is much more vivid. It's easy to follow the gradient across each of the zones even though there are a few exceptions (such as the southwest tip of Georgia which uses 39XXX like central Mississippi). The ZIP+4 code is not required, but it aids the post office in additional sorting of mail. A ZIP+4 code may correspond to a city block, group of apartments, or an individual high-volume receiver.

It is also common for each PO Box number to correspond to a unique ZIP+4 code. Sometimes, several PO Box numbers are grouped into the same ZIP+4 code by using the last several digits of the PO Box number. This method isn't a universal rule though so the ZIP+4 must still be looked up for each PO Box. USA ZIP Code Boundaries Despite the fact that ZIP codes seem to be geographic in nature, that wasn't their intended purpose. Free id card template download.