On July 1, 1963, the U.S. Post Office Department introduced the Zone Improvement Plan, better known as the ZIP Code system. The five-digit codes were designed to speed mail sorting and delivery as mail volume surged in the postwar era. Advertisements and a cartoon character named Mr. ZIP helped educate the public on using the new codes. Businesses adopted ZIP Codes quickly for bulk mail and record-keeping. Over time, additional digits were added for more precision. The system remains essential to addressing, logistics, and demographic analysis in the United States.
