⏵ Course guide · Central Mississippi loop ultra
Big Butts sends the 100K, 50K, 25K, and relay field around a 7.75-mile loop across Mississippi College Choctaw Trails and Butts Park singletrack in Clinton, Mississippi, fast enough that the race itself offers a bounty for a new 100K record. I will walk you through the loop and cutoffs first, then give you a pacing and fueling plan built for a hot Mississippi July day, plus free tools to dial in your own numbers.
These facts come from the official mutsrunning.org site. Entry fee was not published there at the time of writing, so confirm it directly. Course markings and logistics can change year to year.
Every distance at Big Butts shares the same loop across Mississippi College Choctaw Trails and Butts Park, repeated for distance.
Each 7.75-mile loop covers both the Mississippi College cross country trails and the singletrack of Butts Park itself, a mix that keeps the course varied without demanding technical mountain terrain. The 100K works out to a little over eight full loops.
The race provides a Start/Finish aid station and one additional station on the course, both stocked with water, Tailwind sports drink, and food. Because the Start/Finish area comes around on every loop, runners are also welcome to set up personal aid there: tents, coolers, chairs, and whatever nutrition you want waiting for you lap after lap.
The race itself puts a $100 bounty on the table for any 100K runner who beats organizer Peter Kazery's fastest recorded time of 9 hours 42 minutes. That is a strong signal about how runnable this loop is relative to a technical mountain 100K, useful context if you are trying to gauge the course's difficulty against races you already know.
With a shared 7.75-mile loop for the 100K, 50K, and relay, your own splits from lap to lap are the clearest read you will get on how the 14-hour window is actually going.
Run your first loop at a pace you know you can repeat, then compare every following loop against it. Chasing the record-bounty pace from the start is a real temptation on a runnable course like this one, but discipline on the early loops is what protects your ability to hold pace once mid-July heat builds through the day.
For the 100K especially, track your projected finish against the 9:00 PM deadline after every single loop rather than waiting until the later miles. A repeating loop format makes this kind of ongoing math genuinely easy to do, so use that advantage.
⏵ Free tools to pace this course
With Start/Finish aid on every loop, plus whatever personal aid you set up there, you can build a real per-hour fueling plan instead of guessing.
Aim for roughly 60 to 90 grams of carbohydrate per hour while moving and sodium in the 300 to 700 mg per liter range, pushing toward the higher end as the day heats up. Mid-July in central Mississippi means real humidity and heat by mid-morning, so plan your sodium and fluid intake around the conditions, not just the distance.
Because you can set up your own aid station at the Start/Finish, you are not limited to what the race provides. Pre-stage your preferred gels, drink mix, and cold fluids there so every loop gives you a fully customized refuel rather than relying only on the on-course aid.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal distance, and a hot mid-July Mississippi day 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 training plan built around YOUR fitness and the heat and repeat-loop demands of Big Butts. Summit Line reads your real training, builds the durability your distance needs, and rehearses your fueling so race day is something you execute, not guess at.
Every distance is built from the same 7.75-mile loop across Mississippi College Choctaw Trails cross country trails and Butts Park singletrack. The 100K, 50K, and relay runners share a 7:00 AM start and a 14-hour window to finish by 9:00 PM, while the 25K starts a half hour later at 7:30 AM with a tighter 7-hour limit.
The 100K, 50K, and relay all run on a 14-hour clock from a 7:00 AM start, meaning you need to finish by 9:00 PM. The 25K has its own 7:30 AM start and a 7-hour limit. Because every distance is built from repeated 7.75-mile loops, your own lap splits are a direct, honest read on whether you are inside your cutoff.
The organizers themselves offer a $100 bonus to any 100K runner who beats the fastest recorded 100K time of 9 hours 42 minutes, which tells you this is a genuinely runnable Mississippi course rather than a mountain-vert grind. The mix of cross country trails and Butts Park singletrack keeps it interesting without demanding technical mountain skills, and a 14-hour window for the 100K is generous.
Aid is available at the Start/Finish and one additional on-course station, both stocked with water, Tailwind sports drink, and food. Because you pass through the Start/Finish area on every 7.75-mile lap, you can also set up your own personal aid there, coolers, chairs, and whatever nutrition you want waiting for you each loop. Aim for roughly 60 to 90 grams of carbohydrate per hour while moving and sodium in the 300 to 700 mg per liter range, adjusted upward for a mid-July Mississippi day. Build your own numbers with the free ultra fueling calculator.
Yes. The race explicitly allows runners to set up personal aid stations, tents, coolers, and chairs around the start area, which doubles as your aid stop on every loop given the repeating format. That is a real advantage over a point-to-point course, since your own supplies are never more than one 7.75-mile lap away.
The repeating 7.75-mile loop is a strong format for a first attempt at the distance: you learn the course quickly, the Start/Finish aid station (which you can supplement with your own personal setup) comes around on every lap, and 14 hours is a generous window for a course the organizers themselves treat as fast enough to chase records on. Mid-July Mississippi heat is the real variable to respect and plan around, more than the terrain itself.
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<a href="https://runsummitline.com/guides/big-butts">The Big Butts course guide</a><iframe src="https://runsummitline.com/embed/race/big-butts" style="width:100%;max-width:420px;height:180px;border:0;" loading="lazy" title="Big Butts course guide by Summit Line"></iframe>This guide is independent and for planning only. The format, date, and course 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.
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