⏵ Course guide · Stanley Eddy Park Reserve, Minnesota
Eddy Trail Races puts a supportive, well-aided Big Eddy 50K and a hilly Eddy half marathon on the trails of Stanley Eddy Park Reserve, all based out of Chi Rho Center on Lake Sylvia near Annandale, Minnesota, and finishing with a jump in the lake. I will walk you through the two courses first, then give you a pacing and fueling plan built for a warm early-August day. There are free calculators along the way to dial in your own numbers.
These facts come from the official Running Tangents event page. The exact 2026 date is not yet confirmed there as of this writing. Check the current year details before you commit.
Both races run through Stanley Eddy Park Reserve, just different sections and distances, all starting and finishing at Chi Rho Center on Lake Sylvia.
Big Eddy loops through each section of the reserve plus the connecting roads back to Chi Rho Center, and by the race's own account runs closer to 51 or 52 kilometers than a true 50K. With one main aid station visited 6 times and three others visited twice each, 12 aid passes across roughly 32 miles, you are never far from support.
The Eddy covers the south and east portions of Stanley Eddy Park Reserve: 8 miles of trail, 3 miles of gravel, and some pavement at the start and finish. The race's own description calls this section beautiful and scenic while being genuinely hilly and challenging.
Cross the finish line at either race and the tradition is the same: jump in Lake Sylvia. The whole weekend leans into a relaxed, social atmosphere, reinforced by onsite lodging in cabins, dorms, or your own tent, plus six buffet-style meals served across the weekend.
Big Eddy's 10 hour limit works out to a bit faster than 3 miles per hour by the race's own description, a genuinely forgiving pace requirement if you keep moving steadily.
With 12 total aid passes over the course, you get frequent, natural checkpoints to assess your pace and adjust. Do not let the generous 10 hour window tempt you into an overly relaxed early pace, the intermediate "TBD" cutoffs mentioned in the race's own materials suggest there is real pacing structure even if the exact times were not published on the page fetched for this guide.
A 4 hour limit on a genuinely hilly half marathon course leaves less margin than the distance alone suggests. Treat the early trail miles conservatively so the hillier sections do not put your finish time at risk.
⏵ Free tools to plan your effort
Early August in central Minnesota can run warm, and the frequent aid access on both courses gives you a real opportunity to fuel little and often rather than carrying everything yourself.
Aim for roughly 60 to 90 grams of carbohydrate per hour while moving and sodium in the 300 to 700 mg per liter range, adjusted up for a warm day. With a main aid station you pass 6 times, you can plan a lighter self-carry load and restock frequently rather than carrying a full race's worth of supplies from the start.
A 4 hour half marathon needs less total fueling than a 50K, but early-August heat still calls for a real hydration plan, especially across the gravel and pavement sections where shade may be limited.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight and your chosen distance 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 training plan built around YOUR fitness and the hilly reserve terrain Big Eddy and The Eddy both ask of you. Summit Line reads your real training, builds the durability your chosen distance demands, and rehearses your fueling so race day is something you execute, not guess at.
Eddy Trail Races is a weekend of two races based at Chi Rho Center on the south side of Lake Sylvia, near Annandale, Minnesota: Big Eddy, a 50K (actually closer to 51 or 52 kilometers by the race's own account) that loops through Stanley Eddy Park Reserve, and The Eddy, a half marathon covering the south and east portions of the same reserve.
The race runs annually, with results posted for 2022 through 2025, but the official page did not have a confirmed date for the coming edition at the time this guide was written. Third-party race calendars list August 8, 2026, but that has not been confirmed on the official Running Tangents page, so check directly before you book travel or lodging.
Big Eddy, the 50K, has a 10 hour time limit, plus intermediate marker cutoffs the race describes as slightly faster than 3 miles per hour, though the exact intermediate times were listed as "TBD" on the fetched page. The Eddy, the half marathon, has a 4 hour time limit.
Big Eddy loops through each section of Stanley Eddy Park Reserve along with the connecting roads back to Chi Rho Center, with 12 total aid station passes across the 32-mile course, one main aid station visited 6 times and three others visited twice each, so you are rarely far from support. The Eddy is a mix of 8 miles of trail, 3 miles of gravel, and a bit of pavement at the start and finish, through the hillier south and east sections of the reserve.
Big Eddy's frequent aid station passes, one main station you pass 6 times, make it a genuinely supportive course for a first 50K, and the whole weekend is built around a relaxed, social lodge-and-meals format rather than a strictly competitive one. The Eddy half marathon is an approachable shorter option if you want to experience the same reserve and finish-line lake jump without the full 50K distance.
Big Eddy's frequent aid stations, 12 passes over 32 miles, mean you can plan a lighter self-carry load and lean more on course support than a typical 50K. Aim for roughly 60 to 90 grams of carbohydrate per hour while moving and sodium in the 300 to 700 mg per liter range, adjusted for what is likely a warm early-August Minnesota day. The Eddy's shorter 4 hour window means fueling matters less than for Big Eddy, but early-August heat still calls for a real hydration plan. Build your own numbers with the free ultra fueling calculator.
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<a href="https://runsummitline.com/guides/eddy-trail-races">The Eddy Trail Races course guide</a><iframe src="https://runsummitline.com/embed/race/eddy-trail-races" style="width:100%;max-width:420px;height:180px;border:0;" loading="lazy" title="Eddy Trail Races course guide by Summit Line"></iframe>This guide is independent and for planning only. The date shown reflects a race-calendar expectation, not a fully confirmed detail on the official site as of this writing (see the FAQ), and course specifics can change year to year, so confirm directly with the race before you register or run. The fueling and pacing advice is general and not medical advice.
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