There are 11 US Post Offices in Humboldt County serving a total of 10,381 residents equating to 944 residents per post office. It's estimated that approximately 16,569 packages are handled across the 11 county post offices annually. Humboldt County is a county located in the U.S. state of Iowa. As of the 2010 census, the population was 9,815. The county seat is Dakota City. The county was created in 1857 and named in honor of Alexander von Humboldt."