Several Michigan ZIP code directories exist online, including a national ZIP code database directory that is provided by the U. S. Postal Service, which include Michigan ZIP codes available on the USPS website. Other specifically Michigan ZIP code directories can be found by using online search engines.
ZIP, or Zone Improvement Plan, codes are designated to regions by the United States Post Office to help increase mail delivery efficiency. The ZIP code consists of five digits that come together to make a single unique numerical code. The ZIP code is placed at the end of any given American-based address to help alleviate confusion between similar addresses as well as make it easier and faster to distinguish regions during the mail sorting and delivery processes. The ZIP code was first introduced to the American mail sorting and delivery system in 1963. For even more clarity, the United States Postal Service introduced four additional digits at the end of the five digit ZIP code in 1983. The four digits at the end of the ZIP code give mail deliverers and sorters additional information about where specifically an address will be amongst a group of streets, a city block, or within a multi-story building.