There are 7 US Post Offices in Burleigh County serving a total of 54,697 residents equating to 7,814 residents per post office. It's estimated that approximately 87,303 packages are handled across the 7 county post offices annually. Burleigh County is a county located in the U.S. state of North Dakota. As of the 2010 census, the population was 81,308, making it the second-most populous county in North Dakota. Its county seat is Bismarck, the state capital. The county was created on January 4, 1873 and later organized on July 16. Burleigh County is included in the Bismarck, ND Metropolitan Statistical Area, commonly called \"Bismarck\u2013Mandan\"."