Austin, probably the best place in the state of Texas to spot one of its most critically endangered species-- a Texas Democrat-- is now the 11th-largest city in the country and the 4th-largest in Texas. Considering that, one probably would not think of Austin, a city far from any real mountains, as a place with climbing, whitewater kayaking, and mountain biking, yet it has those and more. Welcome to the Barton Creek Greenbelt, a semi-wilderness mostly within the Austin city limits.
Since this ostensibly is a climbing site, this page will focus mostly on the climbing.
Limestone is the rock here. A lot of it is highly polished by generations of climbers, but there are spots that still tear your hands up. Note that because of the polish and because many of the routes here were put up before grade inflation became so rampant, many climbs will feel tough for the grade, maybe even a full grade harder.
Polished Limestone at Seismic Wall
Almost all the routes are bolted, and most of those have sport anchors. There are some toprope routes, some of which can be done off sport anchors and some of which have to be set up from above, and there even is a handful of trad routes. Bouldering exists as well. Sport routes go from 5.6 to 5.13. Trad routes start at 5.4 and go at least to 5.10a.
Look for fossils, too. Sometimes they're right on the routes!
Many of the crags are located adjacent to or near swimming holes. During the warm months, which is like March through October, though winter days in the 80s are not uncommon, it's great to jump in and cool off after climbing (if there's water).
Swimming Hole at Gus Fruh
There are several climbing crags here. From north to south as you follow Barton Creek, they are as follows:
Austin Climbing: Sport Routes & Deep Water Solos by John Hogge is the best beta source for the area. The second edition became available in late November 2016, and a revision will be out in late 2018 or early 2019.
There are a few options for guided climbing, but the best in my opinion is Rock-About.
Barton Creek at Seismic Wall
There are several access points for the Greenbelt; this site covers them all.
The most popular climbing areas seem to be New Wall, Great Wall, Gus Fruh, and Seismic Wall.
To reach the New Wall and Great Wall, exit Mopac at Barton Skyway and go southeast until the intersection with Spyglass Drive.
For Gus Fruh, take Barton Skyway from Lamar Boulevard and turn onto Barton Hills. Drive to the the well-marked trailhead.
Note: the two Barton Skyways do not directly connect, as the Greenbelt splits them. Do not, for example, get off Mopac at Barton Skyway and expect it to take you to Gus Fruh as described above.
If you want to go to Seismic Wall, turn off 360 into the business park just south of the bridge over Barton Creek. Turn left and drive to a marked parking area.