There are 4 US Post Offices in Oregon County serving a total of 10,054 residents equating to 2,514 residents per post office. It's estimated that approximately 16,047 packages are handled across the 4 county post offices annually. Oregon County is a county located in the southern portion of the U.S. state of Missouri. As of the 2010 census, the population was 10,881. Its county seat is Alton. The county was officially organized on February 14, 1845, and was named for the Oregon Territory in the northwestern United States. Home to a large area of the Mark Twain National Forest, Oregon County contains more national forest acreage than any county in the state of Missouri. It also contains the Irish Wilderness, the largest federally protected wilderness area in the state. Hiking, backpacking, and horseback riding opportunities abound on the Ozark Trail and the White's Creek Trail. Canoeing, kayaking, jonboating, and fishing are popular on the Eleven Point River, which is Missouri's only National Wild and Scenic River. Grand Gulf State Park is a Missouri state park just west of Thayer which includes a collapsed karst canyon."