FLINTROCK, TEXAS. Flintrock (Flintrock Hill), eighteen miles northwest of Austin near what is now the Lakeway community in western Travis County, was named for the abundance of flint in the area. A post office opened there in 1875 with Paul Reinke as postmaster. The post office was discontinued in 1882, and mail for the community was sent to Bee Caves. Flintrock was not labeled on the 1946 county highway map.
John J. Germann and Myron Janzen, Texas Post Offices by County (1986).