During the winter of 1811-12 a series of some 1,874 recorded tremors within the New Madrid fault dramatically altered the landscape on some 30-50,000 square miles of land creating Lake Isom in extreme northwest Tennessee. A miniature version of the much larger Reelfoot Lake located approximately 3 miles to the north, Lake Isom National Wildlife Refuge encompasses 1,850 acres. Set aside as an inviolate sanctuary for waterfowl in 1938. Lake Isom NWR is the oldest refuge in Tennessee. Due to the refuge's proximity to the Mississippi River, it has always been an important stopover point and wintering area for waterfowl of the Mississippi Flyway. In recent years, mallard populations peak at nearly 100,000 birds in midwinter, with Canada goose populations occasionally reaching 30,000 birds by mid-January. These often spectacular concentrations are enhanced with a variety of other waterfowl species, as well as several wintering bald eagles. Some 239 species of birds have been documented on the refuge, along with 52 species of mammals and 75 species of reptiles and amphibians. The refuge is managed and staffed by personnel from Reelfoot NWR.