⏵ Course guide · Texas Hill Country, three-day festival
Tejas Trails' Frio Trio packs a Friday Night Trail Ultra 50K, a Saturday 17 mile trail run, and Sunday cross country races into one Texas Hill Country weekend at Bushong Mountain Park, alongside gravel biking, mountain biking, and a float down the Frio River. I will walk you through the trail race lineup first, then give you a pacing and fueling plan built for a night ultra and a multi-day weekend. There are free calculators along the way to dial in your own numbers.
These facts come from the official Tejas Trails event page. Check the current year details, cutoffs, and aid stations before you commit. Race logistics change year to year.
Frio Trio is built as pick-your-adventure endurance weekend rather than a single race. Trail running is the anchor, with gravel biking, mountain biking, stand-up paddleboarding, and a river float layered around it.
The headline trail event is a 50K run in the dark at Bushong Mountain Park, in terrain locally nicknamed the "Swiss Alps of Texas" for its hills and views. Running an unfamiliar 50K course at night, with a headlamp as your only view of the trail, is a genuinely different challenge from the same distance in daylight.
Saturday brings daytime trail races at 17 miles, 8.5 miles, and 5 miles, plus a Summit 5K, a Youth 1 mile, and a cash-prize "King and Queen of the Hill" race. Sunday shifts to non-technical, off-road cross country at 8 miles and 4 miles, plus a Youth 1 mile and a Dog Dash, a gentler close to the weekend after Friday's night ultra.
Tejas Trails offers a Frio Fanatic individual package and a Team Champs package, both built around the same trio: the Friday Night Ultra 50K, the Saturday 17 mile trail run, and the Sunday 8 mile cross country. If you are only running one event, the a la carte options let you pick any single race from the full weekend lineup.
Whether you are running just the 50K or stacking all three Frio Fanatic races, the pacing math changes once darkness and cumulative fatigue enter the picture.
A grade-adjusted pace target still matters on Hill Country terrain, but factor in extra time for reduced visibility on a night 50K. Technical footing that is manageable in daylight takes real concentration and a slower cautious pace by headlamp.
For the Frio Fanatic or Team Champs package, think of your Friday 50K pace as an investment in Saturday and Sunday, not an isolated race. A finish-time estimate for each individual event still helps you plan logistics, but hold back a little more than you would in a standalone 50K.
⏵ Free tools to pace this course
Early October in the Frio River Valley usually brings warm days cooling into comfortable nights, good conditions for a Friday night 50K but still worth planning for.
Aim for roughly 60 to 90 grams of carbohydrate per hour on the Night Trail Ultra 50K. If you are running the Frio Fanatic or Team Champs package, prioritize real recovery nutrition, protein and carbohydrate, between Friday night and Saturday morning rather than treating the weekend as one continuous fueling problem.
Sodium in the 300 to 700 mg per liter range covers most runners. Even though the 50K runs at night, daytime heat leading into the race and warm early-evening temperatures at the Friday start can still leave you dehydrated heading into the cooler overnight hours, so hydrate deliberately before the sun goes down.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a Hill Country night race with the free ultra fueling calculator. Browse the rest of the free running tools at the tools hub.
⏵ Train for it with Summit Line
Get a race-day plan built around YOUR fitness, this exact Hill Country climbing profile, and your projected splits. Summit Line reads your real training, builds a plan for a night ultra or a stacked multi-day weekend, and rehearses your fueling so race day is something you execute, not guess at.
It depends entirely on which race, or which package, you choose. The Night Trail Ultra 50K runs Friday night at Bushong Mountain Park in Hill Country terrain that has earned the region the nickname "Swiss Alps of Texas," and running it in the dark adds a real navigation and fatigue challenge on top of the distance. The Frio Fanatic package stacks that 50K with a Saturday 17 mile trail run and Sunday 8 mile cross country race across three days, which is a serious cumulative endurance test even though no single event is enormous on its own.
The official race page does not publish a specific elevation gain figure for the trail races. What is confirmed is that the trail running events, the Night Trail Ultra 50K, the 17 mile, 8.5 mile, and 5 mile daytime races, and the Summit 5K, take place at Bushong Mountain Park in the Frio River Valley, terrain locally nicknamed the "Swiss Alps of Texas" for its hills and views. Expect real Hill Country climbing rather than a flat course, and confirm current elevation figures on the official race site before you commit to a pacing plan.
The Night Trail Ultra 50K runs Friday night, which means fueling in the dark with cooler October temperatures working in your favor but visibility and navigation working against you. Aim for roughly 60 to 90 grams of carbohydrate per hour, and sodium in the 300 to 700 mg per liter range, and make sure your headlamp and backup light plan is as dialed as your fueling plan for a night race. If you are doing the multi-day Frio Fanatic package, plan your carbohydrate and recovery nutrition across all three days, not just within each individual race. Build your baseline numbers with the free ultra fueling calculator before race day.
Specific cutoff times for the Night Trail Ultra 50K and the other trail distances are not published on the main event page. Check the official Tejas Trails race site for the current runners handbook and aid station cutoff chart before you commit, especially for the Friday night 50K where darkness adds real time pressure beyond the raw distance.
The trail races are based at Bushong Mountain Park in the Frio River Valley, Texas Hill Country, an area known for crystal-clear water, extensive trails, and small-town charm that has earned it the nickname "Swiss Alps of Texas." Early October in this part of Texas typically brings warm days cooling into comfortable nights, good conditions for a Friday night 50K, though Hill Country weather can still surprise you with a warm spell.
The Night Trail Ultra 50K could work as a first ultra if you have real night-running and Hill Country trail experience, since running an unfamiliar 50K course in the dark adds a layer of difficulty a daytime race does not have. If you are newer to the distance, consider the daytime 17 mile trail run instead as a stepping stone, or the shorter 8.5 mile and 5 mile options to experience the venue before committing to the full night ultra in a future year.
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<a href="https://runsummitline.com/guides/frio-trio">The Frio Trio Endurance Festival course guide</a>This guide is independent and for planning only. The course details, dates, cutoffs, and aid stations come from public sources and can change year to year, so confirm the current specifics with the official race before you register or run. The fueling and pacing advice is general and not medical advice.