There are 5 US Post Offices in Freestone County serving a total of 17,960 residents equating to 3,592 residents per post office. It's estimated that approximately 28,666 packages are handled across the 5 county post offices annually. Freestone County is a county located in the U.S. state of Texas. As of the 2010 census, the population was 19,816. Its county seat is Fairfield. The county was created in 1850 and organized the next year."