Mississippi County, organized in 1845 and comprising 411 square miles of Missouri's great alluvial plain, became a major producer of cotton, grain, and soybeans. The Mississippi River, whose name comes from an Algonquin Indian term meaning Great Water, forms about 70 miles of the county's eastern boundary and separates it from Illinois and Kentucky; a boundary dispute over Wolf Island was settled in 1871 in Kentucky's favor by the U.S. Supreme Court. Charleston, the county seat, known as the Cotton Capital and a shoe manufacturing center, was first called Mathews' Prairie for John Mathews, a settler on a Spanish grant there in 1801, and was laid out in 1837 by John Rodney on land belonging to W.P. Bernard, Joseph Moore, and Thankful Randol, with the town named for Chas. Moore. The first settlement was Birds Point across from Cairo, Illinois, where a one-mile bridge built in 1929 crosses the river; John Johnson came there in 1800, and Abraham Bird, later one of the founders of Hannibal, established a trading post and river landing there in 1805. Settled by Kentucky and Tennessee pioneers, the area lay within the 1808 Osage Indian land cession, retains 350 prehistoric mounds, and was violently affected by the New Madrid earthquakes of 1811-12. Mississippi County also contains historic Belmont Battlefield, where on Nov. 7, 1861, Gen. U.S. Grant with 3114 troops saved the forces of Col. R.J. Oglesby from possible capture by engaging 2500 Confederates under Gen. G.J. Pillow in a six-hour battle; Union losses were 485, while the Confederates, who held Belmont, lost 641. A chain was stretched across the river from Confederate-held Columbus, Kentucky, to Belmont in an unsuccessful attempt to stop Union gunboats, and part of that chain is preserved in Columbus-Belmont Battlefield State Park in Kentucky. From 1861 to 1865 the county endured continual war activity. Among towns founded after the war was East Prairie, laid out in 1883 as Hibbard. Two branches of the Missouri Pacific Railroad date from 1869, and the St. Louis Southwestern dates from the late 1890s. In the 1880s large lumber companies arrived to cut the fine forests, and the first levees were built in the 1890s. Big Oak Tree State Park, opened in the county in 1937, covers 1007 acres as a botanical garden with some of the largest oak trees in the U.S. The county was the birthplace of archaeologist Thomas Beckwith and the home of writer and planter Thad Snow.