The Big Tex Backyard Ultra is one of the most difficult running events nationwide,, held each fall at Stephen F. Austin State Park in San Felipe. The format, known as a “backyard ultra,” is simple: every hour, on the hour, runners must complete a 4.167-mile loop. Finish within the hour, and you earn the right to start the next loop. Miss the cutoff and your race is over. The event only ends when one runner remains standing.
The backyard format was created by ultrarunning legend Lazarus Lake, the same mind behind the Barkley Marathons. What began in his Tennessee backyard in 2011 as an experiment in endurance and pacing has since evolved into a global series known as the Backyard Ultra World Championships. The structure’s simplicity has made it one of the fastest-growing disciplines in ultrarunning.
Big Tex, now in its fourth year, has quickly established itself as a test of endurance in Texas. Runners camp near the start/finish area, enduring long days and nights. Those who complete 24 loops, 100 miles, earn a special buckle, while the last runner standing takes home $1 for every mile completed.
In 2025, Kendall Picado Fallas claimed the overall win, completing 22:21:20.26 of racing, that’s 116.66 miles in case you were wondering. On the women’s side, Alyssa McClellan was the top finisher, finishing closely behind Fallas with a time of 22:20:10.06, or 112.5 miles.
The Big Tex Backyard Ultra returns on Saturday, November 7, at Stephen F. Austin State Park in San Felipe, TX. Registration is still open! Runners can sign up via RunSignup on the Big Tex registration page.
Other Backyard Ultras in Texas:
-Summit Backyard Ultra, Marble Falls
-The Backland, Gordonville
-Trails by Moonlight: Snow Moon, Lago Vista
-MATAGORDA: Gulf Coast Trail Running Festival, Matagorda
-Austin’s Rodeo Half Marathon and Rodeo Backyard Ultra, Spicewood
-Exclamation 5.0, Roxton
