Great River National Wildlife Refuge protects a broad stretch of Mississippi River floodplain in Illinois and Missouri north of St. Louis, spanning about 11,600 acres across roughly 120 miles in three main units. Evolving from the former Mark Twain National Wildlife Refuge Complex, it expanded through cooperative agreements, land purchases, and later additions including Bear Creek, Delair, and Fox Island. Some 1990s acquisitions followed the major 1993 flood, when damaged floodplain land became available from willing sellers. The refuge is especially significant for birds and was recognized in 1998 as a globally Important Bird Area, while also serving an educational role for the nearby St. Louis population.