Colorado River Run: 100-Mile & 50-Mile Ultra, 50K, Marathon, Half-Marathon, 10K and 5K

Saturday, April 25, 2026.

Be a part of Tejas Trails Pandora’s Box of Rox! Set on the gorgeous and challenging trails inside Reveille Peak Ranch near Burnet, Texas, this run will be sure to please every trail runner's quest for rugged adventure!

While every racer will get some cool swag, March 31 is the deadline to get a shirt. If you register after March 31, you will get some cool Race Swag! This could be a variety of items like a trucker cap, neck gaiter, etc. It will be a cool Swag Item!

Click Here for Tejas Trails Policies (you really do want to know this stuff!)

AUSTIN'S BACKYARD MARATHON

How Far Will You Go?

"So, the last shall be first, and the first last"

BRONZE TICKET QUALIFIER

Runners on Lake Travis Hill Country trail

Texas Hill Country Paradise

Nestled in the heart of the Texas Hill Country, our event takes place near Lago Vista, just 30 miles northwest of Austin. The course winds around a peninsula jutting into Lake Travis, offering stunning water views and the natural beauty of Central Texas. Experience the perfect blend of challenging terrain and breathtaking landscapes that will keep you motivated hour after hour.

Join us for Austin's Backyard Marathon & Memorial Day Remembrance Run, a unique endurance event that allows you to push your limits in the beautiful Hill Country. This officially sanctioned Backyard Ultra is not just a race, it's a test of mental fortitude, strategic pacing, and physical endurance that will challenge you in ways you've never experienced.

The Backyard Ultra Format

Last Person Standing Challenge

This is an officially sanctioned Backyard Ultra. Complete each 4.167-mile loop within 60 minutes to continue. A new loop starts at the top of each hour.

Following our successful 2025 inaugural event, we are working toward Bronze Ticket qualifying status for 2026. Check back for updates on our certification progress!

Memorial Day Remembrance Run

Set Your Own Challenge for a Memorial Day Remembrance Run

While the last runner standing wins the overall championship and qualifying spot, you're welcome to participate according to your own goals. Many runners choose to complete a specific number of loops rather than competing in the last-person-standing challenge.

You'll earn recognition based on your achievement: Complete 1 loop (4-miles) for a woodallion, 4 loops for half marathon medal, 7 loops for marathon medal, or 8+ loops for ultra medal. Simply notify race staff when you've reached your personal goal.

The Rules for the Last Runner Standing Are Simple

• The course is a 4.167-mile (6.706 km) loop

• A new loop starts at the top of each hour

• Participants must complete each loop within the hour to continue

• Runners are eliminated if they fail to complete a loop in time or choose not to start the next loop

• The last person to complete a loop is declared the overall winner

Race Distance Equivalents

Half Marathon

4 Loops

13.1 miles

Marathon

7 Loops

26.2 miles

50K

8 Loops

31 miles

50 Miles

12 Loops

50 miles

100K

15 Loops

62 miles

100 Miles

24 Loops

100 miles

"This variation in terrain, from exposed shoreline paths to shaded and paved sections, will provide crucial diversity over extended hours of running. The course change also gives runners a mental reset, which can be psychologically significant in a format that tests mental endurance as much as physical stamina."

Awards

Finisher Medal

Complete at least one loop

🏅

Half Marathon Medal

Complete 4 loops (13.1 miles)

🥈

Marathon Medal

Complete 7 loops (26.2 miles)

🥇

Ultra Medal

Complete 8+ loops (33.336+ miles)

🏆

Last Person Standing

Overall winner + Bronze Ticket

👑

What's Included

Event Entry

Access to this unique endurance challenge in the Texas Hill Country

Custom Event T-shirt

Commemorative shirt to remember your achievement

Finisher's Medal

Earn a medal by completing at least one loop

Aid Station Support

Fully stocked aid stations to keep you going hour after hour

Ready to Test Your Limits?

Join us for this unique endurance challenge in the beautiful Texas Hill Country. How many loops can you complete?

REGISTER NOW!

JUNE 27, 2026.

This will be the second event in the 2026 Capt'n Karl's Night Trail Run Series - held at Muleshoe Bend LCRA Recreation Area, approximately 40 miles northwest of Austin in picturesque Spicewood, TX. Muleshoe Bend is located on the scenic Lower Colorado River, Lake Travis region. This course is challenging, rocky, technical with 3094 feet of elevation gain. These trails are deceptively tough, with heat & humidity making Muleshoe Bend a worthy adversary. This is primarily due to the thick foliage & heavy woods, creating a peaceful environment & no wind. Get ready to sweat.

While every racer will get some cool swag, June 4th is the deadline to get a shirt.