This application displays zip code locations on a map of Illinois. Click on a location marker to see the zip code, the name of the city and county. NOTE: During the tests in Windows, this properly worked in Firefox and Internet Explorer. In Chrome, the map became unresponsive, seemed to endlessly load some javascript.
The source of the zip code data is: https://www.gaslampmedia.com/download-zip-code-latitude-longitude-city-state-county-csv/