House mice are not native anywhere in Missouri, or anywhere in North America. NatureServe lists the state population as SNA, an exotic species outside any natural range, since this Old World rodent arrived on the continent stowed away with early European settlement. The 159 records here cluster around Mark Twain National Forest and Ozark National Scenic Riverways not because the mice favor Ozark wilderness, but because those large public landscapes include campgrounds, ranger stations, and other buildings where a commensal rodent finds food and shelter alongside people.
Reports peak in August, when warm weather brings more campers and hikers into contact with the buildings and disturbed edges where mice already live. Indoor sightings are easy to miss and a single resident mouse can be reported more than once, so this count reflects submitted encounters at the human-built edges of these landscapes, not how many mice occupy them.
Full species profile
