St. Louis County GIS Map

St. Louis is one of the most repeated county names in the United States: there are 3 counties named St. Louis spread across 2 states. Each one is a different local government with its own boundary, population and flood maps, so the right GIS map depends on which state you mean.

That is also why a search for St. Louis GIS turns up several unrelated county systems — the name on its own does not tell you which state's mapping office you are after. Pick the state you need below.

Every county page opens an interactive GIS map of that county's official Census boundary, with FEMA flood zones, USGS elevation contours, land cover and school districts you can turn on, plus population, land area and ZIP code data.

Most people searching for St. Louis County mean St. Louis County, Missouri — the largest of them, with a population of about 995,569.