There are 9 US Post Offices in Lawrence County serving a total of 35,276 residents equating to 3,920 residents per post office. It's estimated that approximately 56,304 packages are handled across the 9 county post offices annually. Lawrence County is a county located in the southwest portion of the U.S. state of Missouri. As of the 2010 census, the population was 38,634. Its county seat is Mount Vernon. The county was organized in 1845 and named for James Lawrence, a naval officer from the War of 1812 known for his battle cry, \"Don't give up the ship!\" A previous Lawrence County, established in 1815 with its county seat at what is now Davidsonville Historic State Park in Arkansas, covered much of what is now southern Missouri and the northern third of Arkansas; it became Lawrence County, Arkansas when Arkansas Territory was created from Missouri Territory in 1819. Just before that, in 1818, Missouri divided its part of the old Lawrence County into Wayne County and Madison County; those were later divided into others, including the present Lawrence County."