There are 16 US Post Offices in Boulder County serving a total of 199,356 residents equating to 12,460 residents per post office. It's estimated that approximately 318,194 packages are handled across the 16 county post offices annually. Boulder County is one of the 64 counties of the U.S. state of Colorado of the United States. As of the 2010 census, the population was 294,567. The most populous municipality in the county and the county seat is Boulder. Boulder County comprises the Boulder, CO Metropolitan Statistical Area, which is included in the Denver-Aurora, CO Combined Statistical Area."