The U.S. Postal Service launched the Zoning Improvement Plan (ZIP) Code in 1963 to better handle increasing volumes of mail. Its numbers are easy to understand.

Mr. Zip’s Tip:

The U.S. Postal Service uses more than 10,000 pieces of automated processing equipment to sort nearly half the world’s mail volume.

The first number in the code represents a general geographic area of the nation, “0” in the East, moving to “9” in the West. The next two numbers represent regional areas, and the final two identify specific Post Offices. The lowest number ZIP Code is 00501, a unique ZIP for the Internal Revenue Service in Holtsville, NY. The highest number ZIP Code (99950) is in Ketchikan, AK.

The ZIP+4 Code was introduced in 1983. The extra four numbers allow mail to be sorted to a specific group of streets or to a high-rise building. In 1991, two more numbers were added so that mail could be sorted directly to a residence or business.

Today, the use of ZIP Codes extends far beyond the mailing industry and they are a fundamental component in the nation’s 911 emergency system.

The Postal Service maintains a data base for zip code information and it is the responsibility of any business who uses this data to update their records from postal sources frequently because zip codes can and do change to meet the needs of the Postal Service for sorting mail.

For more information about purchasing stamps, stamps by mail, postal regulations, a free subscription to USA Philatelic magazine, Post Office events, the location of the nearest postal store or contract unit, or for answers to your specific Postal Service questions, contact USPS at 1-800-275-8777, or visit www.usps.com. To schedule a presentation for our community, club or group on how the Postal Service brings the Post Office to your home or office computer, call 239-573-9638.

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Please Note: For broadcast quality video and audio, photo stills and other media resources, visit the USPS Newsroom at www.usps.com/communications/newsroom/welcome.htm.

An independent federal agency, the U.S. Postal Service is the only delivery service that reaches every address in the nation, 149 million residences, businesses and Post Office Boxes, six days a week. It has 34,000 retail locations and relies on the sale of postage, products and services, not tax dollars, to pay for operating expenses. Named the Most Trusted Government Agency five consecutive years by the Ponemon Institute, the Postal Service has annual revenue of $75 billion and delivers nearly half the world’s mail.