⏵ Course guide · Chuckanut Mountains ridgelines
Larrabee Lakes runs 12K, 25K, and 50K through the Chuckanut Mountains and Larrabee State Park near Bellingham, Washington, with up to 6,500 feet of gain on the 50K carved by narrow, time-shaped ridgelines. I will walk you through the course and vert first, then give you a pacing and fueling plan for a punchy, climb-heavy Pacific Northwest course. There are free calculators along the way to dial in your own numbers.
These facts come from the official Evergreen Trail Runs event page. Check the current year details, cutoffs, and aid stations before you commit. Race logistics change year to year.
All three distances start and finish at Fairhaven Park, climbing through Arroyo Park before splitting into their own routes through Larrabee State Park's ridgelines and lakes.
Evergreen's own course notes are direct: "we hope you left some gas in your tank to tackle those punchy climbs and drops along the ridge." The unique geology of the Chuckanut Formation means narrow ridgelines that have been bent and molded by time, so expect repeated short, sharp elevation changes rather than a single sustained climb.
The 50K adds a strenuous out-and-back to the Pine and Cedar Aid Station, a lap around Cedar Lake, and a climb past Fragrance Lake before joining the 25K's ridge trail. Peek-a-boo views of Mt. Baker and Bellingham Bay reward the climbing throughout.
50K runners get the option of a drop bag at the Lost Lake Aid Station (mile 18), a useful marker for splitting your race into two halves mentally and logistically. This is a cupless race, so bring your own hydration vessel throughout.
With three published aid station cutoffs on the 50K, use them as real pacing checkpoints rather than pacing only to the final cutoff.
The 9:45 AM Pine and Cedar cutoff at mile 9, the 12:15 PM Lost Lake cutoff at mile 18, and the 3:00 PM Rock Trail cutoff at mile 24 give you built-in checkpoints across the 50K. A grade-adjusted pace target for the punchy Chuckanut climbs helps you hit each one with margin rather than racing the clock late.
The most demanding climbing, the strenuous out-and-back to Pine and Cedar and the climb back over the ridge from Lake Samish Drive, comes in the middle-to-late stages of the 50K. Pace the early Arroyo Park climb conservatively so you have legs left for that stretch.
⏵ Free tools to pace this course
Early August in Bellingham is typically mild and forested, but 6,500 feet of repeated climbing on the 50K still adds up to a real caloric demand.
Aim for roughly 60 to 90 grams of carbohydrate per hour on the 50K, and sodium in the 300 to 700 mg per liter range. Aid stations sit at roughly 2.5, 9, 18.5, 24.5, and 29 miles on the 50K, giving you frequent chances to reset your intake.
If you take the drop bag option at mile 18, stage exactly what you need for the demanding second half, extra calories, a layer change, or fresh electrolytes, rather than overpacking your race vest for the whole 50K at once.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and 6,500 feet of Chuckanut climbing 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 6,500-foot Chuckanut climbing profile, and your projected splits. Summit Line reads your real training, builds a plan for punchy ridgeline vert, and rehearses your fueling so race day is something you execute, not guess at.
The 50K climbs 6,500 feet, the 25K climbs 2,900 feet, and the 12K climbs 1,500 feet, all published figures from the official course page. Evergreen Trail Runs describes it plainly: "this is a tough race with a significant amount of elevation gain." The 50K's 10 hour window gives real margin, but 6,500 feet of gain packed into 31 miles of Chuckanut ridgeline is a genuine test.
The official course page lists exact figures: 1,500 feet for the 12K, 2,900 feet for the 25K, and 6,500 feet for the 50K. The climbing comes from the unique geology of the Chuckanut Formation, narrow ridgelines shaped and molded by time, so expect repeated punchy climbs and drops rather than one long grade.
Early August in Bellingham is typically mild, but 6,500 feet of climbing on the 50K still demands a real plan. Aim for roughly 60 to 90 grams of carbohydrate per hour, and sodium in the 300 to 700 mg per liter range. This is a cupless race, so bring your own hydration vessel. 50K runners can also stage a drop bag at the Lost Lake aid station (mile 18). Build your numbers with the free ultra fueling calculator before race day.
50K runners face three checkpoints: 9:45 AM at Pine and Cedar (mile 9), 12:15 PM at Lost Lake (mile 18), and 3:00 PM at Rock Trail (mile 24), with the course closing entirely at 5:00 PM, a 10 hour window from the 7:00 AM start. Build your pacing plan against those specific checkpoints, not just the final cutoff.
The course winds through lush green forest and past picturesque lakes, including Fragrance Lake and Cedar Lake, with narrow ridgeline sections shaped by the Chuckanut Formation's distinctive geology. Peek-a-boo views of Mt. Baker and Bellingham Bay show up along the ridges, mixing forest cover and open Cascade and coastal views in the same race.
The 12K and 25K are reasonable trail race entry points, with real but manageable vert (1,500 and 2,900 feet respectively) and a shared, easy-to-navigate Fairhaven Park start/finish. The 50K, at 6,500 feet of gain, is a genuinely demanding first ultra choice: fine if you already have real vertical trail experience, but not the gentlest introduction to the distance.
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<a href="https://runsummitline.com/guides/larrabee-lakes">The Larrabee Lakes course guide</a>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.