Zion Ultras (Zion 100) Course Guide

The mesa walls: short, steep, and the only real climbing

Almost all the vert here lives in four big climbs up onto the mesas, each roughly 1,000 to 1,500 feet, including the early Flying Monkey climb and the Gooseberry Mesa ascent. They are short and steep enough that you hike them, and that is fine. Hike them with purpose, eat on the way up, and do not race the person next to you. The mistake is treating these like the whole story and grinding them hard. They are punctuation, not the sentence.

Up top the mesas are slickrock and tight, twisty singletrack with huge red-rock views out over the desert and the Red Bull Rampage cliffs. The footing is technical and the rock can be slick when it is dusty or damp, so quick feet and attention matter as much as fitness. These mesa loops are where you can quietly lose time if you check out, so stay sharp on the rock.

The desert in between: fast, flat, and a trap

Between the mesas you get sandy washes, ATV roads, and rolling desert that runs fast, and this is the real trap of the Zion 100. It feels easy. You are not climbing, the miles tick by, and it is tempting to bank time on the flats. Do that and you arrive at the next mesa wall, or worse the night, with nothing left. Run the runnable desert at an effort you could hold for hours, keep eating, and let the easy terrain be easy instead of fast.

The sand and the exposure are their own tax. Loose, soft footing burns more than it looks like it should, and there is almost no shade out here, so the sun is on you for hours. Treat the flat desert as the place you protect your legs and your stomach, not the place you make a move.

The night: the late loops are where it is decided

On the 100 mile the back end drops into a set of desert loops in the dark, and that is where the race actually gets decided. The temperature falls hard once the sun is gone, your pace sags, the slickrock gets confusing under a headlamp, and the easy desert you flew across in daylight turns into a long mental grind. Get your light and your warm layer before dark, not after you are already cold and fumbling.

This is the stretch the 36-hour cutoff is built around. Keep moving, keep eating even when you do not want to, and break the night into aid-station-to-aid-station chunks instead of staring at how far is left. People who keep their feet moving through the 2 a.m. low finish this race. People who sit down and get cold often do not.

Aid, drop bags, and the long gaps

The 100 mile has more than a dozen aid stations around the loop, a mix of fully stocked and water-only, but the spacing varies and some desert and mesa stretches run long and exposed between them. Do not assume the next aid is close. Carry enough fluid and calories to cover the gaps, especially across the hot midday and the open mesas, and refill to the brim every time even when you think you are fine.

Set drop bags at the bigger accessible stations with your night kit, your backup nutrition, fresh socks, and anything you know your race-brain will forget. If you are running unsupported, those drop bags are your crew, so stock them like it.

Pace by effort and grade, not by your flat splits

Your road pace means nothing on the mesa climbs and not much on soft desert sand either. What matters is grade-adjusted effort: hike the mesa walls at a steady output, then settle the runnable desert into an easy effort you could hold all day. The classic Zion blowup is hammering the flat middle because it feels free and arriving at the night with empty legs. Use a grade-adjusted pace to turn your real fitness into honest targets for both the climbs and the flats, and you will not cook the first half.

Build a vert-aware, cutoff-aware finish prediction

Do not guess your Zion finish off a road time or a flat 100 PR. The 10,500-plus feet of mesa climbing, the sand, the heat, and the night all add real time, and the 36-hour cutoff with intermittent checkpoints means you need to know your margin, not just your goal. Build a vert-aware finish prediction for this course, then work it backward into the aid-station cutoffs so you know exactly how much buffer you should have at each one instead of finding out the hard way.

Carbs: steady all day, and keep eating in the dark

Aim for around 60 to 90 grams of carbohydrate per hour, leaning to the higher end early when your gut still works, and only that high if you have trained it. The heat and the long hours kill your appetite, so favor steady, easy-to-stomach calories over big late doses you will not want. The hard part is the night: when you stop feeling hungry around 2 a.m. is exactly when you have to keep feeding the machine. Set a timer, eat on it, and practice your race-day carb rate on long runs so it feels normal, not like an experiment.

Sodium and fluid: built for dry desert and long gaps

Dry desert air hides how much you are sweating because it evaporates before you notice, so do not let a lack of obvious sweat fool you into underdrinking or underdosing salt. Lean toward the high end on sodium, often around 500 to 700 milligrams per liter of fluid, and more if you are a heavy or salty sweater. Carry enough to cover the long, exposed gaps between aid instead of rationing to the next station and showing up empty. Weigh yourself before and after a hot, dry long run to find your real sweat rate, then build the plan around your own number.

Crew: fast, warm, and keeping you honest

A crew at the accessible aid stations is a big lever on the 100. Their job is to get you in and out fast, swap your bottles and your nutrition, and hand you a warm layer and a charged light before the sun goes down, not after you are already shivering. Just as important, they keep your fueling honest when your brain quits late: if you have not been eating, they make you. Give them a sheet with your in-and-out time targets and your night-kit plan so they are running the same race you are.

Pacers and drop bags: company for the dark miles

Pacers are typically allowed on the back portion of the 100 mile, so confirm the exact mileage and rules in the current race guide and put your strongest, calmest friend on the night loops. A good pacer keeps you moving through the 2 a.m. lows, reads the slickrock when you stop trusting your own feet, and talks you out of the chair. If you are running unsupported, your drop bags are your crew: stock the bigger stations with night layers, a backup light, fresh socks, and the foods you know you will still tolerate when nothing sounds good.