There are 5 US Post Offices in Douglas County serving a total of 64,854 residents equating to 12,971 residents per post office. It's estimated that approximately 103,514 packages are handled across the 5 county post offices annually. Douglas County (county code DG) is a county located in the U.S. state of Kansas. As of the 2010 census, the county population was 110,826, making it the fifth-most populous county in Kansas. Its county seat and most populous city is Lawrence."