 Its eastern boundaries with Jasper County and Orange County are formed by the Neches River.The southern boundary with Jefferson County is formed by Pine Island Bayou


As of the 2010 census, Hardin County had a population of 54,635.The ethnic and racial composition of the population was 88.0% non-Hispanic white, 5.8% African American, 0.4% Native American, 0.5% Asian, 1.3% from some other race, and 1.3% from two or more races.