There are 8 US Post Offices in Osage County serving a total of 12,397 residents equating to 1,550 residents per post office. It's estimated that approximately 19,787 packages are handled across the 8 county post offices annually. Osage County is a county located in the central portion of the U.S. state of Missouri. As of the 2010 census, the population was 13,878. Its county seat is Linn. The county was organized January 29, 1841, and named from the Osage River. Osage County is part of the Jefferson City, MO Metropolitan Statistical Area. Its geography and the founding of Westphalia Vineyards links it to the Missouri Rhineland, extending along the Missouri River valley to the western edges of the St. Louis Metropolitan Area. Westphalia Vineyards, although started only in 2005, won the gold medal in the National Norton Festival Wine Competition in St. Louis in 2007 for the top-rated wine from the Norton grape. According to data from the 2010 census, Osage County is the whitest county in Missouri, with 98.85 percent of residents being white."