Round Rock, Built in Layers
Round Rock is named for the round, anvil-shaped rock in Brushy Creek where wagons and, later, cattle on the Chisholm Trail crossed. The town grew up on the creek banks in 1851, and today it is a city of nearly 120,000 people and the international headquarters of Dell. It also straddles the Balcones Escarpment: east of I-35 the land is flat blackland prairie with heavy clay soil locals once called black waxy, and to the west it climbs into rocky Hill Country. That split, plus more than a century of building, means a Round Rock house can have very different HVAC needs depending on when and where it was built.
