Williamson_County,_Texas | largestCity | Round_Rock,_Texas Austin,_Texas | isPartOf | Williamson_County,_Texas Williamson_County,_Texas | countySeat | Georgetown,_Texas Austin,_Texas | isPartOf | Travis_County,_Texas
Austin is part of Williamson County, Texas and is located in Travis County. Georgetown is the county seat of Williamson County, Texas, where Round Rock is the largest city.