FLATT, TEXAS. Flatt, on the Colorado River ten miles northwest of Austin in west central Travis County, took its name from Cameron Flatt, the name of the surrounding region. The community had a store and a blacksmith shop in 1892. That same year a post office opened there with Wiley H. Milam as postmaster, but it was discontinued the following year, and the community's mail was sent to Bee Caves. Flatt was not marked on county highway maps in the 1940s.