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Worlds End Ultramarathon Course Guide

The Worlds End Ultramarathon is a technical 100K and 50K through Loyalsock State Forest and Worlds End State Park, built on rugged, rock-strewn singletrack past narrow gorges, waterfalls, and a cliffside water crossing. The 100K is also one of the very few Western States 100 qualifiers on the East Coast. I will walk you through the course, then give you a pacing and fueling plan built for technical terrain and a long day, plus free tools to dial in your own numbers.

⏵ At a glance

Worlds End Ultramarathon quick facts

Date
Late May or early June (2026: May 30)
Location
Forksville, PA, Worlds End State Park (Cliff Pavilion) and Loyalsock State Forest
Distances
100K (marquee) and 50K
Elevation gain
100K: about 12,000 to 12,400 ft · 50K: about 5,900 ft
Start / cutoff
100K: 5 AM start, 19 hr limit (midnight) · 50K: 7 AM start, 12 hr limit (7 PM)
Qualifier
100K is a Western States 100 (WSER) qualifier, one of the few on the East Coast; requires a prior qualifying 50K within 3 years plus RD approval
Entry
Field caps around 200 (100K) and 250 (50K), first-come registration opening about 6 months out on RunSignup

These facts come from the official race site. Aid station cutoff splits and current entry pricing can change year to year, so confirm the current specifics on worldsendultra.com before you commit.

The course: technical from the first mile

Both distances start and finish at the Cliff Pavilion in Worlds End State Park, running out through Loyalsock State Forest on rugged, rock-strewn singletrack. The 100K climbs roughly 12,000 to 12,400 feet, the 50K about 5,900 feet, and neither distance gives you much smooth trail to recover on.

Endless shorter climbs, not one big mountain

Worlds End does not hand you a single defining climb the way some mountain ultras do. Instead you get endless shorter climbs stacked one after another, with a steepest pitch around 1,000 rocky feet. That adds up to real vert without ever giving you a long, steady rhythm to settle into, so the climbing here punishes inconsistent effort more than it rewards raw power.

The rocky, technical footing means your legs work harder per mile than the elevation numbers alone suggest. Quick feet and patience on the rocks matter as much as fitness.

The gorges: Ketchum Run and the cliffside water section

The course threads through narrow gorges and rocky hollows, with Ketchum Run Gorge as one of the signature features. You pass Rode Falls, Lee's Falls, and Alpine Falls along the way, plus a cliffside water section that demands full attention. This is the heart of the race, technically. Slow down here and pay attention. It is not the place to push pace on tired legs.

High Rock Vista and Canyon Vista give you the payoff views, but do not let the scenery pull your focus off your footing on the rocky trail between them.

Cutoffs and the shape of a long day

The 100K starts at 5:00 AM with a 19 hour overall limit, closing at midnight. The 50K starts at 7:00 AM with a 12 hour limit, closing at 7:00 PM. Individual aid station cutoffs along the way are not something we can verify here, so pull the current cutoff sheet from worldsendultra.com before race day and build your plan against it.

Pacing strategy for technical, stacked terrain

With endless shorter climbs instead of one big mountain, and rocky footing the whole way, Worlds End rewards steady effort and technical patience over aggressive pace targets.

Pace the climbs by effort, not by a flat-ground number

The stacked, shorter climbs at Worlds End add up fast if you attack each one individually. What matters is grade-adjusted effort held consistently across the whole day, so you are not blowing up on the tenth climb because you ran the first three too hard. Use a grade-adjusted pace to turn your real fitness into honest targets for this kind of terrain, and the rocky footing stops feeling like a constant fight.

Set a realistic finish window against the cutoffs

A road ultra time or even a smoother trail time will not translate directly to Worlds End. The endless climbing and technical footing both add real time. A vert-aware finish prediction that accounts for this course gives you a realistic window to work backward from the 19 hour (100K) or 12 hour (50K) overall limit, so you know your actual margin instead of guessing.

⏵ Free tools to pace this course

Fueling strategy for a long technical day

The 100K likely runs somewhere in the 12 to 19 hour range for most finishers, and technical terrain slows digestion the same way it slows your legs. Keep the fueling plan simple and rehearsed.

Carbs: steady and simple over technical miles

Aim for around 60 to 90 grams of carbohydrate per hour, leaning toward the higher end only if your gut is trained for it. Technical footing means less attention available for complicated fueling routines, so keep your intake simple and predictable. Practice your exact race-day carb rate on rocky, technical training runs so it is second nature by race day.

Sodium and fluid: match the day's conditions

Sodium in the 300 to 700-plus milligram per liter range, scaled to how hot the day runs, covers most Worlds End finishers. Carry enough fluid to cover the gaps between aid, especially through the gorge sections where the terrain slows you down more than the mileage suggests. Weigh yourself before and after a long, technical training run to find your real sweat rate.

⏵ Build your fueling plan

Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and the Worlds End terrain 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 Worlds End course profile, and your projected splits. Summit Line reads your real training, builds a plan for the stacked climbing and technical footing, and rehearses your fueling so race day is something you execute, not guess at.

Start free →Explore the demo

Worlds End Ultramarathon FAQ

How hard is the Worlds End Ultramarathon?

Worlds End is a genuinely tough technical mountain ultra, and the organizers themselves call it "not an entry-level race." The 100K climbs somewhere around 12,000 to 12,400 feet over rugged, rock-strewn singletrack in Loyalsock State Forest, with endless shorter climbs rather than one big one, plus a steepest pitch around 1,000 rocky feet. Add in narrow gorges, rocky hollows, and a cliffside water section, and you get a course that rewards technical trail skill as much as raw fitness. The 50K, at around 5,900 feet of gain, is more approachable but still demands real technical footwork.

How much climbing is in the Worlds End 100K and 50K?

The 100K climbs roughly 12,000 to 12,400 feet (the race states both figures) over its full distance, spread across endless shorter climbs on rugged singletrack rather than one dominant mountain. The steepest individual pitch runs around 1,000 rocky feet. The 50K climbs about 5,900 feet, a smaller but still demanding profile on the same technical terrain. Both distances start and finish at the Cliff Pavilion in Worlds End State Park.

Is the Worlds End 100K really a Western States qualifier?

Yes, and it is one of only a handful of East Coast races with that status. A finish at the Worlds End 100K counts toward the Western States 100 (WSER) lottery, which is rare for a race this far east. To run the 100K here you need a prior qualifying 50K finish within the last 3 years plus race director approval, so it is not open entry. If chasing a WSER qualifier is part of your season plan, confirm the current qualifying standards on worldsendultra.com before you register, since WSER's own rules get updated periodically.

How should I fuel for the Worlds End Ultramarathon?

The 100K is a long day on demanding technical terrain, likely somewhere in the 12 to 19 hour range depending on your pace, so plan carbohydrate intake around 60 to 90 grams per hour and sodium in the 300 to 700-plus milligram per liter range depending on conditions. Technical footing slows digestion just like it slows your pace, so keep your fueling simple and rehearsed rather than complicated. The 50K is shorter but still calls for a real plan given the terrain. Build your numbers with the free ultra fueling calculator before race day.

What are the Worlds End Ultramarathon cutoffs?

The 100K starts at 5:00 AM with an overall limit of 19 hours, closing at midnight. The 50K starts at 7:00 AM with a 12 hour limit, closing at 7:00 PM. Cutoffs at individual aid stations along the way are not something we can verify here, so confirm the current aid station cutoff sheet on the official race site before you build your pacing plan around them.

What is the terrain like at Worlds End?

Expect rugged, technical, rock-strewn singletrack through Loyalsock State Forest and Worlds End State Park, past landmarks like High Rock Vista, Canyon Vista, Ketchum Run Gorge, and a run past Rode, Lee's, and Alpine Falls. Rocky hollows, narrow gorges, and a cliffside water section round out a course that is technical from start to finish rather than technical in one section. This is a course where quick feet and patience on the rocks matter as much as fitness.

This guide is independent and for planning only. The course details, dates, cutoffs, qualifying standards, and entry pricing 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.