⏵ Course guide · Eastern Washington desert ultra
Ancient Lakes builds every distance, 10K through 50 Mile, from a repeating cloverleaf loop system through Quincy's desert coulees, a waterfall, ancient desert lakes, and the Columbia River Gorge. I will walk you through the loop breakdown first, then give you a pacing and fueling plan built for exposed, rolling desert terrain. Free calculators along the way to dial in your own numbers.
These facts come from the official Run Super Series race page. Race logistics change year to year, so confirm the current specifics before you commit.
Every distance is built from a three-loop, 25K cloverleaf system: red, green, and blue loops, each starting and ending at a common aid station.
The first loop of the sequence takes you by a waterfall and basalt rock outcroppings, a distinctive start to the day that also happens to be your first return to the central aid station, useful for gauging how the terrain is treating you before the longer distances repeat it.
The second loop runs out to yet another lake and features a return trip through canyon-like desert terrain, single track with rolling up and down that never exceeds 400 feet on any one climb or descent, but adds up across repeated passes for the longer distances.
The third loop drops down into the Columbia River Gorge, runs along the river, then climbs back out and rolls to the finish (or back to the start for another lap on the longer distances). This is the loop with the most dramatic terrain change, river-level running followed by a climb back to the plateau.
The 25K runs red-green-blue once (1,700 ft, ~17 miles actual). The Marathon adds a second red and green loop on top (~2,800 ft). The 50K runs the entire 25K sequence twice (3,400 ft, ~34 miles actual). The 50 Mile runs it three times (~6,000 ft, ~51.5 miles actual). Every lap returns to the same aid station, so your drop bag access repeats predictably regardless of which distance you choose.
With no single climb or descent over 400 feet but continuous rolling terrain repeated multiple times for the longer distances, even pacing across loops matters more than pushing any one section.
Because the 50K and 50 Mile simply repeat the same 25K sequence, a grade-adjusted pace target for the rolling terrain, applied consistently across every lap, keeps you from front-loading effort on a "fresh legs" first loop that later laps cannot match.
The 50 Mile carries a hard cutoff at mile 44.2 (5:30 PM), separate from the overall 14-hour finish window. Use a race-time prediction to check your projected arrival at that specific mileage, not just your projected finish time, since missing that intermediate cutoff ends your race regardless of how much time remains on the overall clock.
⏵ Free tools to pace this course
Eastern Washington coulee terrain offers little shade, and April temperatures can range from a cool trailhead start to a warm, exposed afternoon on the plateau sections.
Aim for roughly 60 to 90 grams of carbohydrate per hour. Because every loop passes the same central aid station, use that repetition to keep intake steady rather than carrying a full race's worth of supplies from the start.
Sodium in the 300 to 700 mg per liter range covers most runners, and the largely shadeless coulee and canyon terrain can push sweat losses higher on a sunny day regardless of which distance you are running. Adjust upward if the forecast calls for a clear, warm April Saturday.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and an exposed eastern Washington desert 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 and this exact repeated desert-loop profile. Summit Line reads your real training, builds the heat tolerance and rolling-terrain durability the course demands, and rehearses your fueling so race day is something you execute, not guess at.
The 50K climbs 3,400 feet over an actual course length of about 34 miles, built from running the 25K loop system twice. No single climb or descent on the 25K loop exceeds 400 feet, so the difficulty comes from accumulated desert-terrain rolling rather than one defining mountain. Add exposed, largely shadeless coulee terrain and this is a course where heat and pacing discipline matter as much as raw elevation.
Every distance is built from a repeating 25K loop structure made of three smaller loops, red, green, and blue, each starting and ending at a common aid station. The 25K runs all three once (about 17 miles actual, 1,700 ft gain). The Marathon runs the full 25K once plus a second red and green loop (~2,800 ft). The 50K runs the entire 25K course twice (3,400 ft, ~34 miles actual). The 50 Mile runs it three times (~6,000 ft, ~51.5 miles actual). Because every loop returns to the same start/finish area, drop bag and aid access repeats predictably no matter which distance you choose.
The red loop passes a waterfall and basalt rock outcroppings. The green loop runs out to another lake and returns through canyon-like desert terrain. The blue loop drops down into the Columbia River Gorge, runs along the river, then climbs back out and rolls to the finish. Trails are primarily single track with rolling terrain, and the course design deliberately keeps any single climb or descent under 400 feet, favoring cumulative rolling difficulty over one big feature.
Eastern Washington desert coulees in April can run cool at the trailhead but exposed and warm once the sun is fully up over open canyon sections. Aim for roughly 60 to 90 grams of carbohydrate per hour, and keep sodium in the 300 to 700 mg per liter range, adjusting upward on a warm day. The 50 Mile's aid stations at miles 4, 8, 12, 17.5, 21, 27.2, 34, 38, and 44.2 give frequent resupply, and mile 44.2 carries a hard cutoff (5:30 PM) that you must clear before continuing. Build your numbers with the free ultra fueling calculator before race day.
The Marathon carries an 8-hour cutoff, the 50K a 9-hour cutoff, and the 50 Mile a 14-hour cutoff, with a hard intermediate cutoff at mile 44.2 (5:30 PM) for 50 Mile runners specifically. Given that no single climb exceeds 400 feet but the terrain rolls continuously across repeated loops, respect these windows rather than assuming "no big mountain" means an easy pace.
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<a href="https://runsummitline.com/guides/ancient-lakes-trail-runs">The Ancient Lakes Trail Runs course guide</a><iframe src="https://runsummitline.com/embed/race/ancient-lakes-trail-runs" style="width:100%;max-width:420px;height:180px;border:0;" loading="lazy" title="Ancient Lakes Trail 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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