There are 3 US Post Offices in Jackson County serving a total of 1,394 residents equating to 465 residents per post office. It's estimated that approximately 2,225 packages are handled across the 3 county post offices annually. Jackson County is the fourth-least densely populated of the 64 counties of the state of Colorado. As of the 2010 census, the population was 1,394,. The county seat and only incorporated municipality in the county is Walden."