There are 1 US Post Offices in Hinsdale County serving a total of 802 residents equating to 802 residents per post office. It's estimated that approximately 1,280 packages are handled across the 1 county post offices annually. Hinsdale County is one the 64 counties of the U.S. state of Colorado of the United States. As of the 2010 census, the population was 843, making it the third-least populous county in Colorado. With a population density of only 0.75 inhabitants per square mile (0.29/km2), it is also the least-densely populated county in Colorado. The county seat and only incorporated municipality in the county is Lake City. The county is named for George A. Hinsdale, a prominent pioneer and former Lt. Governor of Colorado."