Williamsburg Township covers an area of 56.43 square miles (146.2 km) and contains one incorporated settlement, Williamsburg. According to the USGS, it contains one cemetery, Mount Hope.
The stream of Mill Creek runs through this township.
Silkville. Founded by Ernest de Boissiere in 1870, Silkville was based entirely on the silk industry. The small community thrived until 1892 when de Boissiere donated the ranch to the Independent Order of Odd Fellows and returned to France.