Liberty County is a county located in Texas within the HoustonSugar LandBaytown metropolitan area. As of the 2010 United States Census, the population was 75,643. Its county seat is Liberty. The Trinity River flows through this county, dividing the county approximately in half. The river begins on the northern border of Liberty County, forming the San Jacinto - Polk County line through the Liberty County line. The east fork of the San Jacinto River flows through far Northeast parts of the county, Flowing through Cleveland. Tarkington Bayou begins in the Sam Houston National Forest in San Jacinto County, working its way south through Northeast and east Liberty County and joining other feeders, before traveling into Harris County and emptying into Galveston Bay. The highest point in Liberty County is "Davis Hill", the roof of a salt dome in the northern part of the county.