The Great River National Wildlife Refuge protects approximately 11,600 acres along 120 miles of the Mississippi River, stretching north of St. Louis, Missouri. Three separate units are located in the floodplain, on both the Illinois and Missouri sides of the river. In 1998, the Great River Refuge was designated as a globally important bird area, due to its value to shorebirds, songbirds, and waterfowl. The refuge's proximity to St. Louis provides excellent educational opportunities to a large population. The Clarence Cannon National Wildlife Refuge is also under the administration of the Great River Refuge. Great River Refuge, in turn, is part of the Mark Twain National Wildlife Refuge complex, which also includes Port Louisa, Two Rivers, and Middle Mississippi River refuges. The complex headquarters is in Quincy, Illinois.