Headwaters of the Frio Marathon / Half Marathon

About the Course​ ​


Big Springs Ranch is 11.5 miles long and up to 4 miles wide. Most of the 7,050 acres are virtually untouched by humans with fewer than 100 visitors per year. The course winds through a wide variety of spectacular terrain.

You will climb to the top of ridges and descend to river valleys, traverse canyons, forests and meadows, ford streams and run past Big Springs, the very source of the Frio River. Water and aid stations will be located approximately every two miles along the course.

There is an incredible variety of animal and plant life along the trail. While planning the route, we photographed Whitetail deer, Red deer, Axis, Aoudad, Wild Pigs, Coyotes, Horses, Longhorn Cattle, Wild Turkey, Jackrabbits, Lizards, Snakes, Scorpions, Turtles, Bullfrogs, Butterflies, Osprey, Red Tailed Hawks, Great Blue Herons, Hummingbirds and other birds too numerous to list (over 200 bird species have been identified on the ranch).

The route is a treat for the senses as you run/walk under the shade of Live, Bur, and Chinquapin Oak trees, smell the cedars, see Texas Mountain Laurel, and walk through native grasses punctuated with the vivid hues of Bluebonnets, Indian Paintbrush and a tremendous variety of wildflower species.

The few traces of man’s presence are relics of a bygone age: an 1896 homesteader’s cabin and gravesite, a model T car from Mexico abandoned along the road north, a campsite where a Chicago gangster hid out in the 1930’s and there’s even rumor of buried treasure near Horse Collar Bluff.

However, stretching back much further in time, the most incredible aspect of the route is you will literally run/walk in the footprints of dinosaurs! There are two areas of dry riverbed with dozens of well preserved tracks of a variety of dinosaur species. This is truly one of the most unique and interesting marathon courses in the world!

There are only 150 spots available for this event, so get your registration in soon!


[ Trail map in progress. Will go here. ]