Williamson County given the âgreen lightâ to become vaccination hub Williamson County given the âgreen lightâ to become vaccination hub County officials want to emphasize that, for right now, the hub plan is not for the general public. WILLIAMSON COUNTY, Texas - The Family Emergency Room clinic in Cedar Park is part of Williamson County's vaccine hub plan, which is coordinated by the county's Office of Emergency Management. Unlike a single hub, like in Arlington, the plan is for at least 3 satellite distribution sites, according to Williamson County Judge Bill Gravell. "Bu...