Flint Hills National Wildlife Refuge (NWR) is a wildlife refuge located north and east of the city of Hartford, Kansas, United States, in northwestern Coffey and southeastern Lyon Counties. It was established in 1966 as part of the U.S. Army Corps of Engineers, John Redmond Reservoir flood control project. The U.S. Fish and Wildlife Service manages 18,463 acres (75 km²) upstream of the reservoir, most of which is in the floodplain of the Neosho River.