There are 5 US Post Offices in Prowers County serving a total of 12,779 residents equating to 2,556 residents per post office. It's estimated that approximately 20,397 packages are handled across the 5 county post offices annually. Prowers County is one of the 64 counties in the U.S. state of Colorado. As of the 2010 census, the population was 12,551. The county seat is Lamar. The county is named in honor of John W. Prowers, a leading pioneer in the lower Arkansas valley region."