Williamson County (sometimes abbreviated as “Wilco”) is a county in the U.S. state of Texas. As of the 2016 census estimate, the population was 545,412. Its county seat is Georgetown.The county is named for Robert McAlpin Williamson (1804?–1859), a community leader and a veteran of the Battle of San Jacinto.
Williamson County is part of the Austin-Round Rock, Texas Metropolitan Statistical Area. It was included with Austin in the Best Cities to Live in for 2009 by the Milken Institute. It is on both the Edwards Plateau to the west, rocky terrain and hills, and Texas Blackland Prairies in the east, rich, fertile farming land. The two areas are roughly bisected by Interstate 35.