Pleasanton is a city in Atascosa County, Texas, United States. The population was 8,266 at the 2000 census. Pleasanton's official motto is "The City of Live Oaks and Friendly Folks." It is part of the San Antonio-New Braunfels Metropolitan Statistical Area. Pleasanton was established in 1858 when conflicts with the Indians caused the settlers to move the location of the county seat from Amphion. The settlers chose the current town site because of its location at the mouth of Bonita Creek. John Bowen (d.1867), San Antonio's first Anglo-American postmaster, founded and named the town of Pleasanton after his good friend and fellow Early Texas Settler John Pleasants.