Near the south rim of the Chisos Mountains of the 800,000 acre Big Bend National Park, the 27 mile Glen Springs Loop follows rutted old wagon roads that are open to mountain biking. It starts at the intersection of Glen Springs Road and Black Gap Road.
Also, make sure to check out the 27 mile Old Ore Road rough through the foothills of Dead Horse Mountain. It can be pretty rough and rocky.
Overall, Glen Springs Loop is the 15th most popular mountain bike trail of all 59 mountain biking rides in Texas.