There are 5 US Post Offices in Lucas County serving a total of 8,917 residents equating to 1,783 residents per post office. It's estimated that approximately 14,233 packages are handled across the 5 county post offices annually. Lucas County is a county located in the U.S. state of Iowa. As of the 2010 census, the population was 8,898. The county seat is Chariton. The county was formed in 1846 and was named for Robert Lucas, a Governor of the Territory."