There are 4 US Post Offices in Crook County serving a total of 20,763 residents equating to 5,191 residents per post office. It's estimated that approximately 33,140 packages are handled across the 4 county post offices annually. Crook County is a county located in the U.S. state of Oregon. As of the 2010 census, the population was 20,978. The county seat is Prineville. The county is named after George Crook, a U.S. Army officer who served in the American Civil War and various Indian Wars. Crook County comprises the Prineville, OR Micropolitan Statistical Area, which is included in the Bend-Redmond-Prineville, OR Combined Statistical Area."