⏵ Course guide · Central New York
Green Lakes Endurance Runs repeats an ~8-mile loop through Green Lakes State Park, 2 times for the 25K, 4 for the 50K, and 8 for the 100K, mixing shaded forest climbs with an open meadow section the race calls "the Serengeti." I will walk you through the loop and its warm-weather stretch, then give you a pacing and fueling plan built for repeated laps, with free calculators along the way.
These facts come from the official UltraSignup registration page. Check the current year details, cutoffs, and aid stations before you commit. Race logistics change year to year.
Every fixed-distance race at Green Lakes shares the same ~8-mile loop. The 25K runs it twice, the 50K four times, and the 100K eight times, so learning that one loop well pays off no matter which distance you race.
Each loop climbs twice through shaded upland forest with some roots, ruts, and stones underfoot, then gives you back one long descent to the lower lake section. That lower stretch near the start/finish is shaded, mostly flat, and generally easy footing, a natural place to recover before starting the next lap.
The upper meadow section, more than 3 miles of it per loop, is nicknamed "the Serengeti" by the race team for its open, rolling, completely unshaded character. On a hot, sunny August day this is where the course punishes you most, regardless of how the elevation profile reads.
If you are running the GLER Galeforce 12-Hour Race rather than a fixed distance, note that it uses its own 3-mile clockwise loop around Green and Round Lakes only, skipping the upland forest and Serengeti sections entirely. Pace and terrain expectations for that race differ meaningfully from the 100K/50K/25K loop.
Because you repeat the same loop, your early laps give you real data to work with for every lap that follows, a real advantage over a point-to-point course.
A grade-adjusted pace target for the loop's two climbs, checked against how your first lap actually felt, lets you set a repeatable effort for every subsequent loop rather than guessing blind. Runners who go out too hard on loop one almost always feel it hardest in the Serengeti section of loop three or four.
A vert-aware finish-time projection built from your actual early loop splits, extrapolated across the remaining laps, is far more honest than any flat-course time estimate. Check that projection after your first or second loop while you still have plenty of laps left to adjust.
⏵ Free tools to pace this course
Late August here tends to run warm and can turn humid, and the open Serengeti section of each loop is where that heat shows up most in your fueling and hydration needs.
Aim for 50 to 70 grams of carbohydrate per hour, and use the predictable start/finish aid access every loop to keep your intake consistent rather than skipping a lap here or there. The loop format makes steady fueling easier than most ultras, so take advantage of it.
Keep sodium in the 400 to 600 mg per liter range as a baseline, and push toward the higher end for laps run during the warmest part of the day, particularly through the exposed meadow section. The shaded lakeside stretch of each loop is a good place to reassess how you are handling the heat before heading back up into the forest.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a warm central New York 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 8-mile Green Lakes loop, and your projected lap splits, so race day is something you execute, not guess at.
The course is described by the race team as extremely runnable as trail courses go, with well maintained singletrack, grassy trail, and a bit of dirt road and asphalt woven through an ~8-mile loop. The two climbs and one long descent per loop add up over repeated laps, four for the 50K, but this is a course built for consistent, quick running rather than technical hiking.
Every fixed-distance race, the 100K, 50K, and 25K, runs the same ~8-mile loop repeated: 8 times for the 100K, 4 times for the 50K, and 2 times for the 25K. The GLER Galeforce 12-Hour Race is different, using a separate, shorter 3-mile clockwise loop that circles only the lower Green and Round Lakes section, so timed-race runners see less of the upland forest terrain than the fixed-distance fields.
With loop-based racing, you pass the start/finish and its aid station every lap, so you can plan your fueling around a predictable rhythm rather than guessing at spacing. Aim for 50 to 70 grams of carbohydrate per hour on the 50K and 100K, and use the fact that you are never more than 3.75 miles from aid to keep your intake steady lap after lap rather than overloading early.
Each ~8-mile loop climbs twice through shaded upland forest with some roots, ruts, and stones, then descends one long stretch back down. The upper meadow section, nicknamed "the Serengeti" by the race team, runs mostly dirt and grass, rolling and completely unshaded, which can turn into the toughest 3-plus miles of each loop on a warm, sunny August day. The lower lake section near the start/finish is shaded, flat, and generally easy underfoot.
Central New York in late August typically runs warm and can turn humid, and the open, unshaded "Serengeti" meadow section of the loop is where that heat shows up most. Plan your hydration and pacing around that stretch specifically rather than treating the whole loop as uniformly shaded, since the lakeside sections stay noticeably cooler.
The loop format is a strong choice for a first ultra: you pass the start/finish area every lap, which makes crew access, mental math, and drop bag use far simpler than a point-to-point course, and the terrain itself is described as quick and non-technical. The 25K, at two loops, is an approachable stepping-stone distance if the 50K feels like too much for a first attempt.
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<a href="https://runsummitline.com/guides/green-lakes-endurance-runs">The Green Lakes Endurance Runs course guide</a><iframe src="https://runsummitline.com/embed/race/green-lakes-endurance-runs" style="width:100%;max-width:420px;height:180px;border:0;" loading="lazy" title="Green Lakes Endurance Runs 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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