Williamson County Texas is covered by a total of 32 ZIP Codes. There are 14 ZIP Codes in Williamson County that extend into adjacent counties (Bastrop County, Bell County, Burnet County, Lee County, Milam County, and Travis County). Of the ZIP codes within or partially within Williamson County there are 21 Standard ZIP Codes, 1 Unique ZIP Codes and 9 PO Box ZIP Codes.
Click on the ZIP Codes in the interactive map to view more information. The map control in the upper right corner can be used to toggle map layers on and off. The red outline is the border of Williamson County and can be turned on and off. Each type of postal code can also be turned on and off.