Bull Creek is a tributary of the Colorado River originating in the Texas Hill Country. The creek passes through some of the more scenic areas in the Austin region and forms a greenbelt that is the habitat for many indigenous species of flora and fauna. It runs beneath steep slopes and benches surfaced with shallow clay loams that support ashe juniper, escarpment live oak, mesquite, and grasses.
The creek begins in north central Travis County (at 30°23′42″N 97°50′20″W / 30.395°N 97.839°W) and flows approximately 12 miles (19 km) southeast through Austin to Lake Austin, where it merges with the Colorado River (at 30°20′51″N 97°47′30″W / 30.3475°N 97.7918°W).