Enchanted Rock is a granite dome occurring in the Enchanted Rock State Natural Area, a state park located in central Texas. Located on the southeast margin of the large Enchanted Rock Batholith, the granite exposed is one of the Town Mountain Granite suite and is of Precambrian age. U-Pb zircon geochronology gives an age of 1082+-6 million years old (Walker, 1992) which corresponds to the late Proterozoic subdivision of the Precambrian. Precambrian rocks in central Texas are part of the Llano Uplift. There are several large exfoliation domes and castle tors in the park. The largest (Enchanted Rock itself) rises 122 m (> 400 ft) above the surrounding landscape. ER is has been claimed to be the second largest exfoliation dome in the U.S., Stone Mountain is definitely larger, Independence Rock is definitely smaller. ER is simply the best place to look at granite in Texas.

Getting there:
From Llano, Texas-- drive south on Rte. 16 around 22 km (13 miles) to Ranch Road 965 (on the right, just after you cross Sandy Creek). Turn right and it's about 13 km (8 miles) further to the park.
From Fredericksburg, Texas-- drive north on Ranch Road 965. It's a ways, about 30 km (18 miles), but worth the trip. Very scenic route and some day I hope to drive it in a Porsche.

A detailed road log, starting in Fredericksburg, going to the Park, and continuing on to the town of Burnet, is available for download.

Other web sites discussing Enchanted Rock.

Sources of detailed geologic information on ERSNA and the Enchanted Rock Batholith.

What's this "second largest" thing??

The organization you should thank for the ERSNA being there.