Two Rivers National Wildlife Refuge protects riverine bottomland wetlands at the confluence of the Illinois and Mississippi rivers in western Illinois and nearby Missouri. Managed by the U.S. Fish and Wildlife Service within the Mark Twain National Wildlife Refuge Complex, it covered 8,501 acres in 2009 across five separate parcels. The refuge extends through parts of Calhoun, Jersey, and Greene counties in Illinois and St. Charles County, Missouri, with headquarters in Brussels, Illinois. Especially noted for its bald eagle population, it preserves an important floodplain landscape and exemplifies the river-bottom habitats that characterize this stretch of the Mississippi and Illinois valleys.