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⏵ Course guide · New Mexico ultra

Day of the Dead Series Course Guide

The Day of the Dead Series in Las Cruces is the opposite of a brutal mountain hundred, and that is the whole point. It is a flat, fast, fully-supported fixed loop along the Rio Grande where you can chase a 100 mile, 100K, or 50K buckle without a single real climb, which makes it one of the best first-hundred courses in the country. I will walk you through how the loop format actually races, then give you a pacing and fueling plan built for a flat, long day. There are free calculators along the way to dial in your own numbers.

⏵ At a glance

Day of the Dead Series quick facts

Date
A two-day weekend in late October (run one day or both)
Location
La Llorona Park, along the Rio Grande, Las Cruces, New Mexico
Distances
100 mile, 100K, 50K, plus marathon, half, 10K, and 5K
Elevation gain
Essentially flat. A fast USATF-certified out-and-back loop, the lowest, flattest course in New Mexico
Start
7:00 AM, with an optional 6:00 AM early start (bring a light)
Cutoff
Generous. Early-start 50K runners get roughly 9.5 to 10 hr, early-start 100K about 14.5 to 15 hr, and the 100 mile runs until 7:00 PM Sunday
Award
A finisher belt buckle for the long distances, one of the only 100 mile buckle races in New Mexico
Qualifier
No Western States, Hardrock, or UTMB Running Stones status listed by the race

These facts come from the official race site and public ultra listings. The exact date, start times, and cutoffs move year to year, so check the current race-day details before you commit. Race logistics change.

The course: where the Day of the Dead is won and lost

Forget climbs and switchbacks. This is a short out-and-back loop, about 1.1 miles each way, on a paved path with a crushed-gravel lane beside it, run over and over along the Rio Grande at La Llorona Park. It is USATF-certified and billed as the flattest, lowest course in New Mexico. So the race is not won on the terrain. It is won in your head and in your stomach.

The loop: your biggest weapon and your biggest trap

The loop is the whole story here. You pass the main aid station roughly every mile, which means you are never far from your drop bag, your crew, your spare bottle, or a chair. That is a massive advantage. You can carry almost nothing, top off fluid constantly, change socks the second something feels off, and break a hundred miles into chunks you can actually hold in your head.

The flip side is mental. The same stretch of path on repeat will start to grind on you somewhere in the back half, usually right when the novelty wears off and the fatigue shows up. The runners who do well here stop thinking about the full distance and start running lap to lap, gel to gel, aid stop to aid stop. Give your brain a tiny target and keep feeding it one.

Flat and fast, which is its own kind of hard

No climbs sounds easy, and the finish times are fast, but a pancake-flat course beats up your body in a way hills do not. There is no downhill to coast on and no uphill that forces you to hike and give your legs a different motion, so it is the same stride, the same muscles, the same impact, for hours. That repetition is what catches flat-course first-timers off guard.

Train for it by getting in genuinely flat, monotonous long runs, not just hilly trail time. Practice walk breaks on the flat (a deliberate walk through each aid lap is a great reset), and get your feet used to long hours on a hard, even surface so the bottoms of your feet and your hip flexors do not become the thing that ends your day.

Day into night, and the long quiet hours

At the 100K and 100 mile distances you will be out there into the dark, so the loop becomes a night course for a stretch. The good news is you are still passing that aid station every mile and your crew is right there, so the night is far less lonely and far less risky than it is on a remote mountain hundred. Still, have a light ready for the optional early start and for the evening, and plan for the temperature swing.

Southern New Mexico in late October is high desert, so expect a real range: pleasant or even warm in the afternoon sun, then a sharp drop after dark. Stage warm layers, a hat, and gloves in your drop bag so you can grab them on a lap instead of suffering a cold patch. The late, quiet hours are where a hundred is truly run, and on this course they are as forgiving as they come.

Pacing strategy for a flat fixed-loop ultra

With no climbs to hide behind, pacing here is brutally honest. There is no terrain to slow you down early, so the temptation to bank time is strong, and giving in to it is the classic way to fall apart in the back half. The cutoffs are generous, so you do not need to be a hero early.

Start slower than feels right, then hold

On a flat course your early miles feel absurdly easy, and that is the trap. Every blown flat-course hundred starts with banking a cushion in the first marathon that you pay back with interest later. Pick a goal pace that is genuinely conversational, run it from the gun, and let the people who went out hot come back to you in the night. Even effort wins flat ultras.

Because the loop is short and certified, your splits are clean data: you can watch your lap times and catch yourself drifting fast (or slow) almost in real time. Use a recent race result to set an honest goal pace before race day rather than guessing on the morning, and trust the plan when your legs feel great at mile 20.

Work backward from the cutoffs

The cutoffs here are forgiving (early-start 50K runners get around 9.5 to 10 hours, and the 100 mile runs until 7:00 PM Sunday), but you should still know your numbers. Build a realistic finish prediction, then work back to a per-lap or per-section average so you always know whether you are ahead of the clock. On a loop you get that feedback constantly, which is a gift: small course corrections beat one panicked late surge.

A flat course makes prediction easier than a mountain race because there is no vert to muddy the math, so your equivalent road or trail times translate cleanly here. Set a target, set a hard floor (the pace that keeps you safely inside cutoffs), and ride between them.

⏵ Free tools to pace this course

  • Grade-adjusted pace calculator to confirm what flat really means for you, and to translate your hilly training runs into honest flat-course targets.
  • Race-time calculator for a finish prediction you can break into per-lap splits and plan against the cutoffs.
  • Race-equivalent calculator to turn a recent race result into a Day of the Dead goal you can actually hold for the whole distance.

Fueling strategy for the flat, long day

On a flat, fully-aided loop, fueling is the thing that decides your day. There are no climbs to blame and no remote gaps to survive, so the runners who finish strong are almost always the ones who never let their stomach fall behind. The course basically hands you a buffet every mile, so use it.

Carbs: steady, trained, and easy on a flat course

Aim for around 60 to 90 grams of carbohydrate per hour, and only push the higher end if your gut is trained for it. The flat surface is a huge advantage here: you can eat and drink almost continuously because you are not gasping up a climb or hammering a descent, so there is no reason to slip behind on calories. Set a fueling clock, take something in every lap, and do not wait until you feel low to eat.

The biggest flat-course mistake is treating "easy terrain" as "I can wing the fueling." You cannot. A hundred miles is a hundred miles, and the stomach is what fails first. Rehearse your exact race-day carb rate on long runs until 70 to 90 grams an hour feels routine.

Sodium, fluid, and the aid station you pass every mile

Keep sodium coming the whole way, more if it is warm in the afternoon sun or you are a heavy, salty sweater, somewhere in the 300 to 700 milligrams per liter range and up from there for big sweaters. The aid station you pass roughly every mile means you can run light, top off fluid constantly, and never carry a heavy pack, so take that gift and stay topped up rather than rationing.

Weigh yourself before and after a long run to find your real sweat rate, then build the plan around your own number instead of a generic one. Use your drop bag at the loop to pre-portion gels, salt, and bottles so every pass through aid is fast and you are not standing around doing math at mile 80.

⏵ Build your fueling plan

Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a flat all-day effort 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 flat fixed-loop format, and your projected splits. Summit Line reads your real training, builds the long flat endurance and durability this course demands, and rehearses your fueling so race day is something you execute, not guess at.

Start free →Explore the demo

Day of the Dead Series FAQ

How hard is the Day of the Dead Series?

Physically it is one of the most approachable ultras out there, because the course is flat, fast, and fully supported on a short out-and-back loop along the Rio Grande in Las Cruces. There is almost no climbing and the footing is easy, so the difficulty is not the terrain, it is the distance and the repetition. The cutoffs are generous (early-start 50K runners get roughly 9.5 to 10 hours, and the 100 mile runs all the way until 7:00 PM Sunday), so the real challenge at the longer distances is staying patient and not letting the loops mess with your head. That is exactly why it has a reputation as a great first 100K or first hundred.

Is the Day of the Dead Series a good first 100 miler or first 100K?

Yes, it is one of the better places in the country to attempt a first hundred. You get a flat, non-technical course, an aid station you pass roughly every mile, generous cutoffs, and full crew and pacer access because you are never far from the start. There is no big climb to blow your legs up and no remote section where things can go wrong far from help. If you can cover the distance and you respect your fueling, the format gives a prepared first-timer a very fair shot at the buckle.

How much elevation gain is in the Day of the Dead Series?

Almost none. The course runs on a paved path with a crushed-gravel lane alongside it on a 1.1-mile-out, 1.1-mile-back loop next to the Rio Grande, and the race bills it as the flattest, lowest course in New Mexico. There is no meaningful climbing to train for, which flips the usual ultra math: you are not pacing by grade, you are pacing by patience and your gut. Confirm the current course map with the race, but plan for flat.

What are the cutoff times for the Day of the Dead Series?

The cutoffs are friendly by ultra standards. Early-start 50K runners get roughly 9.5 to 10 hours, early-start 100K runners get about 14.5 to 15 hours, and the 100 mile has until 7:00 PM on Sunday to finish. The race is known for a no-runner-left-behind policy and tends to stay until the last finisher is in. These are approximate and shift year to year, so confirm the exact limits and start times in the current race details before you commit.

What is the loop format like and how do I keep my head in it?

The course is a short out-and-back loop, about 1.1 miles each way, that you run over and over, passing the main aid station every lap. The upside is huge: you can stash drop bags, see your crew constantly, and break a hundred miles into bite-size pieces. The downside is mental, because the same scenery on repeat can grind on you in the late miles. Run by your watch and your fueling clock rather than the scenery, give yourself small targets (the next lap, the next gel, the next aid stop), and the loop becomes a strength instead of a slog.

How should I fuel for the Day of the Dead Series?

Because the course is flat and fully aided, fueling is the single biggest thing that decides your day, more than fitness. Aim for a steady carbohydrate intake of roughly 60 to 90 grams per hour (push the high end only if your gut is trained for it), keep sodium coming, and use the aid station you pass every lap instead of carrying a heavy load. The flat surface lets you eat and drink almost the whole time, so there is no excuse to fall behind on calories. Run your own numbers for your weight, goal time, and the conditions with the free ultra fueling calculator.

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.