⏵ Course guide · Michigan coast-to-coast
Thumb Coast Ultra runs coast to coast across Michigan's Thumb region, mostly dirt roads from Harbor Beach on Lake Huron to Caseville on Saginaw Bay, framed by the organizer as a sunrise-to-sunset challenge. I will walk you through the point-to-point structure first, then give you a pacing and fueling plan built for a long, mostly non-technical road day, plus free tools to dial in your own numbers.
These facts come from the official Trivium Racing event page. Cutoffs, aid, and the exact next-year date can change, so confirm the current details before you register or run.
The 50 Mile and relay run point-to-point, starting in Harbor Beach on Lake Huron and finishing in Caseville on Saginaw Bay. The 50K runs a separate, shorter course entirely within Caseville.
The route follows mostly dirt roads through Michigan's Thumb, a region the organizer calls a hidden gem. Expect a well-marked, largely non-technical surface, which shifts the challenge from footing to sustained distance and pacing across a full point-to-point day.
The organizer frames the 50 Mile explicitly as a sunrise-to-sunset run, coast to coast, with additional prizes for anyone who "beats the sun" to the finish. That framing is a useful pacing anchor even if you are not racing for the bonus: know your available daylight and plan your effort against it.
Because the 50M and relay start and finish in different towns, roughly the width of the Thumb apart, plan your own or your crew's transportation between Harbor Beach and Caseville in advance. The 50K avoids this by starting and finishing in the same location, Caseville, which simplifies logistics if you are not ready for the full point-to-point distance.
With generous cutoffs and mostly dirt-road terrain, the main pacing question is how to sustain effort across the full point-to-point distance, not how to survive one hard climb.
If you are chasing the "beat the sun" bonus, work backward from actual sunset time in late April to set your required average pace, then build in a buffer since aid stops and later-race fatigue both slow you down more than early splits suggest.
A finish-time projection built from your early splits, checked periodically against the daylight or the generous cutoffs, tells you honestly whether your current pace holds up over the full distance, especially useful on a course without one obvious hard section to gauge yourself against.
⏵ Free tools to pace this course
Non-technical terrain does not mean an easy fueling day, a long point-to-point crossing still burns through your carbohydrate and sodium reserves over the course of a full sunrise-to-sunset effort.
Aim for roughly 60 to 90 grams of carbohydrate per hour, using the well-marked, well-stocked aid stations along the route to stay on a consistent schedule rather than letting a smooth, runnable surface tempt you into skipping planned fueling stops.
Keep sodium in the 300 to 700 mg per liter range. Late April in Michigan's Thumb can swing from cool and damp to unexpectedly warm, so check the forecast close to race day and adjust your sodium and hydration plan rather than locking in a single number months in advance.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a long sunrise-to-sunset 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 point-to-point coastal profile, and your projected splits. Summit Line reads your real training, builds a plan for a long sunrise-to-sunset day, and rehearses your fueling so race day is something you execute, not guess at.
It is a genuine coast-to-coast crossing of Michigan's Thumb region: the 50 Mile and relay start in Harbor Beach on Lake Huron and finish in Caseville on Saginaw Bay, running mostly dirt roads the whole way. That point-to-point, water-to-water structure is the defining feature, framed by the organizer as running "sunrise to sunset from one coast to another." The 50K runs a separate, shorter course based entirely in Caseville.
The organizer pitches it as approachable, "perfect for beginners, seasoned vets, and those looking for a personal best," with generous cutoffs and well-marked, mostly dirt-road terrain rather than technical singletrack. The real challenge is less about steep climbing and more about covering the full point-to-point distance before sunset, especially for 50 Milers chasing the "beat the sun" bonus.
The 50 Mile race is framed as a sunrise-to-sunset challenge: cover the full point-to-point distance from Harbor Beach to Caseville before the sun goes down, and the organizer offers additional prizes for finishers who pull it off. Even if you are not chasing that bonus specifically, treat it as a useful mental framework for pacing a long point-to-point day.
With mostly dirt-road terrain and well-stocked aid stations along the route, aim for roughly 60 to 90 grams of carbohydrate per hour and sodium in the 300 to 700 mg per liter range, adjusted for late April weather in Michigan's Thumb, which can range from cool and damp to unexpectedly warm depending on the year. Build your numbers with the free ultra fueling calculator before race day.
The organizer explicitly markets it toward beginners as well as experienced runners, and the mostly dirt-road, non-technical terrain with generous cutoffs supports that pitch. If your primary trail-ultra concern is technical footing rather than raw distance, a point-to-point road-and-dirt ultra like this is a reasonable place to start, provided you plan for the point-to-point logistics of getting yourself and any crew between two coastal towns.
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<a href="https://runsummitline.com/guides/thumb-coast-ultra">The Thumb Coast Ultra course guide</a><iframe src="https://runsummitline.com/embed/race/thumb-coast-ultra" style="width:100%;max-width:420px;height:180px;border:0;" loading="lazy" title="Thumb Coast Ultra 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.