Lake Isom is a small natural lake and swamp in northwestern Tennessee, just south of Reelfoot Lake, within the unusual landscape created by the 1811–1812 New Madrid earthquakes. Fed by Running Reelfoot Bayou, Reelfoot Lake’s outlet stream, it is shallow and swampy, with the lake and surrounding wetlands covering 1,846 acres. Protected as Lake Isom National Wildlife Refuge since 1938, it has remained almost entirely undeveloped because of long-term federal ownership and the refuge’s modest size. Heavy siltation has made the lake even shallower over time, though better agricultural practices have slowed that process. Compared with nearby Reelfoot Lake’s more developed shoreline, Lake Isom remains quieter and less built up.