Liberty is a city in the U.S. state of Texas, within metropolitan area. The population was 8,397 at the 2010 census. It serves as the seat of Liberty County.Liberty is the third oldest city in the state—established in 1831 on the banks of the Trinity River. The city also has a twin of the Liberty Bell from Philadelphia, Pennsylvania. Its area code is 936 and its ZIP code is 77575.HistoryLiberty, Texas is the county seat of Liberty and the third oldest town in Texas. Texas heroes William B. Travis, Sam Houston, and David Burnet all practiced law in Liberty. Three brothers from Liberty died at the Alamo, while some 50 Liberty citizens fought in the Battle of San Jacinto in 1836 when Texas won its independence. Liberty is located on U.S. Highway 90 in the south central part of Liberty County and the Houston, Texas Metropolitan Area. The site is in a major oil and gas production area served primarily by the Union Pacific Railroad. Liberty once stood at the head of navigation, both steamboat and barge, on the Trinity River.The town was founded by Mexican land commissioner José Francisco Madero Gaxiola in 1831 near the sites of a Spanish settlement called Atascosito (established in 1756) and Champ d'Asile, a French colony established in 1818. The area was first occupied by American squatters as early as 1818, when it was still under Spanish law. Settlers along the Atascosito Road, which crossed the Trinity three miles to the north of the present Highway 90 western city entrance, petitioned unsuccessfully to be included in Stephen F. Austin's colony.