There are 6 US Post Offices in Crook County serving a total of 6,753 residents equating to 1,126 residents per post office. It's estimated that approximately 10,779 packages are handled across the 6 county post offices annually. Crook County is a county located in the northeastern section of the U.S. state of Wyoming. As of the 2010 census, the population was 7,083, making it the third-least populous county in Wyoming. Its county seat is Sundance."