The Texas Hill Country is a region of Central Texas, USA, that features rolling, somewhat rugge, hills that consist primarily of limestone. The Hill Country terrain can be seen in San Antonio's northern suburbs and Austin's western suburbs. The region is the eastern portion of the Edwards Plateau bounded by the Balcones Fault on the east and the Llano Uplift to the west and north. The terrain is punctuated by a large number of limestone rocks and boulders and a thin layer of topsoil which makes the region prone to flash flooding.