⏵ Course guide · Poconos ultra
Boulder Field Ultra sends its 18 Miler, 50K, and 100K fields through Hickory Run State Park in the Pennsylvania Poconos, past the park's famous glacial boulder field and the technical "Shades of Death" trail, with about 4,000 feet of climbing on every 50K loop. I will walk you through the course and its technical features first, then give you a pacing and fueling plan built for a race that mixes moderate trail with two genuinely hard sections. There are free calculators along the way to dial in your own numbers.
These facts come from the official Uber Endurance Sports event page. Check the current year details, cutoffs, and aid stations before you commit. Race logistics change year to year.
The entire race is contained within Hickory Run State Park, run as a figure-8 shaped 50K loop. 100K runners simply complete that loop twice. The course is 90% trail, with only 1 mile of gravel road in the whole route.
Hickory Run State Park is home to a genuinely famous geological feature, a field of glacial boulders that gives this race its name. The crossing itself is under a mile, but it is a real hands-and-feet scramble, not running terrain, and the official course notes call it very difficult even though most of the rest of the loop is only moderate. Practice moving efficiently over loose, uneven rock before race day, not just running fitness.
The second defining technical section is the roughly mile-long "Shades of Death" trail, named for its rugged, unforgiving character. Like the boulder field, it is called out separately from the rest of the moderate-difficulty loop, so expect your pace to slow dramatically here regardless of how fresh your legs feel entering it.
The 50K hits aid at miles 5, 10, 12, 15, 21.5, and 26, roughly every 5 to 6 miles. The 100K adds stops at miles 31, 36, 41, 43, 45, 51.5, and 57 on its second loop, and the 18 Miler gets aid at miles 3, 9.5, and 14. Every station carries Gatorade, water, and snacks, and the race requires you carry at least 16 oz of fluid between them, a reasonable rule given the technical sections that will slow your pace unpredictably.
This course does not punish you evenly. Most of the loop is moderate, mid-level technical trail, but the boulder field and Shades of Death sections will eat far more time than their mileage suggests, so plan your pacing around that reality, not a flat average.
A grade-adjusted pace target works well for the roughly 4,000 feet of gain across the moderate parts of the 50K loop, but do not expect that same pace to hold through the boulder field or Shades of Death. Treat those two sections as their own separate efforts, more about careful footing than speed, and let your overall pace plan account for a real slowdown there rather than assuming a constant rhythm.
With generous but real cutoffs (14 hours for the 50K, 16 for the 100K), a vert-aware finish prediction built off the roughly 4,000 feet of gain per loop gives you a solid baseline, but budget extra time on top of that estimate for the boulder field and Shades of Death, since neither runs at anything close to your normal trail pace.
⏵ Free tools to pace this course
With aid every 5 to 6 miles on the 50K and even more frequently on the 100K, you have plenty of chances to restock, so build a plan that uses that access rather than overloading your vest.
Aim for roughly 60 to 90 grams of carbohydrate per hour. Gatorade, water, and snacks are provided at every aid station, but the race requires carrying at least 16 oz of fluid between stops, so plan your carry capacity around the 5 to 6 mile gaps rather than assuming you can refill constantly.
Mid-September in the Poconos can still run warm and humid. Keep sodium in the 300 to 500 mg per liter range for cooler stretches, and push toward 500 to 700 mg per liter if the day turns hot, especially given how much the technical sections will slow you down and extend your total time on course.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a warm Poconos 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 race-day plan built around YOUR fitness, this exact Hickory Run climbing profile, and your projected aid station splits. Summit Line reads your real training, builds a plan for both the moderate loop and the technical boulder field and Shades of Death sections, and rehearses your fueling so race day is something you execute, not guess at.
Uber Endurance Sports bills it as an advanced-difficulty challenge, and the course backs that up with about 4,000 feet of gain per 50K loop plus two genuinely technical features: the mile-long "Shades of Death" trail and the sub-mile boulder field crossing that gives the race its name. The rest of the course is mostly moderate singletrack, so the difficulty is concentrated rather than constant, which can catch runners off guard if they treat the whole loop as easy. The 100K, running that same loop twice, doubles both the vert and the technical exposure.
The official course page states approximately 4,000 feet of gain per 50K loop, with mid-level technical difficulty overall. The 100K covers the same figure-8 shaped loop twice, so expect roughly 8,000 feet of cumulative gain across the full distance. The climbing is spread across a course that is 90% trail, with just 1 mile of gravel road in the entire loop.
These are the two defining technical features of the course. The boulder field crossing is short, under a mile, but crosses Hickory Run State Park's famous field of glacial boulders, a genuine hands-and-feet scramble rather than running terrain. The "Shades of Death" section runs about a mile through the park's most technical trail. Both are called out as very difficult even though the rest of the course is only moderate, so budget real time for them rather than expecting a steady pace throughout.
With aid stations roughly every 5 to 6 miles on the 50K (miles 5, 10, 12, 15, 21.5, and 26) and even more frequent stops on the 100K, you have regular chances to restock. Aim for roughly 60 to 90 grams of carbohydrate per hour, and sodium in the 300 to 700 mg per liter range depending on how warm mid-September runs in the Poconos. Carry at least 16 oz of fluid between aid stations as the race requires, and build your full numbers with the free ultra fueling calculator before race day.
The 18 Miler starts at 7:30 AM with a 13:30 hour time limit. The 50K starts at 7:00 AM with a 14 hour limit. The 100K starts earliest, at 5:00 AM, with a 16 hour limit that puts the course close at 9 PM. All three limits are on the generous side for their distances, especially given the technical Shades of Death and boulder field sections, but always confirm the current cutoff details before you commit to a distance.
The 18 Miler is a genuinely hiker-friendly on-ramp, explicitly built with generous time limits for the 18M and 50K distances and billed as a good introduction to the park's rugged beauty. The 50K is a reasonable first-ultra choice if you have some technical trail experience, since the boulder field and Shades of Death sections demand real scrambling skill, not just fitness. The 100K, doubling both the vert and the technical exposure, is better saved for after you have a finished 50K or two under your belt. Whichever distance you pick, train specifically for scrambling over boulders, not just running.
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<a href="https://runsummitline.com/guides/boulder-field-ultra">The Boulder Field Ultra course guide</a><iframe src="https://runsummitline.com/embed/race/boulder-field-ultra" style="width:100%;max-width:420px;height:180px;border:0;" loading="lazy" title="Boulder Field Ultra course guide by Summit Line"></iframe>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.
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