Zip (Zone/Zoning Improvement Plan announced in PB20362(5/16/63), a combination of 552 3 digit sectional centers at the time plus 2 digit postal zones used since 1943, effective 7/1/63 and Post Office closings since July 1 1963. Not all PO received zip codes between that date and their own closing) CodeUSPS(United States Postal Service®)/ZCTA since 2000 Census (Zip Code™USPS Tabulation Area)U.S. Census Bureau, (see STF3B summary for 1980 and 1990 data) Texas Post OfficeUSPS LineageNCsoft Information Page. USPS not trademarked because it also stands for United States Power Squadrons®. The +4 code was added in 1983. Robert Aurand Moon is considered the father of the zip code. He first submitted his proposal in 1944 while working as a postal inspector. The U.S. Post Office Department only gave credit to Moon for the first 3 digits of the zip code. “Mr. ZIP Code” died on April 10, 2001 at 83 years of age in Leesburg FL 34748.