Some Indiana ZIP codes include 46204 for central Indianapolis, 46802 for central Fort Wayne and 47405 for Indiana University in Bloomington. Approximately half of Indiana ZIP codes start with 46. The other half start with 47.
The website UnitedStatesZIPCodes.org provides both map-based and list-based directories of American ZIP codes. The website allows searches by state, city, county or ZIP code.
The United States Postal Service introduced ZIP codes in 1963. They replaced a previous postal-zone system used in some large cities. USPS made ZIP codes mandatory in 1967 for most bulk mailers, and ZIP codes soon became widely used. USPS uses three types of ZIP codes: standard ZIP codes, P.O. Box-only ZIP codes and unique ZIP codes, which are used for high-volume addresses.