JONESTOWN, TEXAS. Jonestown is on Farm Road 1431 and Lake Travis, twenty miles northwest of Austin in northwestern Travis County. It was established in the late 1930s by Emmet A. Jones and his brother, Warren. The community was incorporated in the 1980s and reported a population of 683 in 1988. In 1990 its population was 1,250. The population increased to 1,681 by 2000.