⏵ Course guide · Central Valley / Sierra foothills
The San Joaquin River Trail 50K rolls along Millerton Lake and the San Joaquin River through the Sierra foothills near Friant, California, with an 11-hour cutoff and aid stations every 5 miles. I will walk you through the course and cutoff math, then give you a pacing and fueling plan for the rolling foothill terrain, with free calculators along the way.
These facts come from the official race page and RunSignUp registration listing. Check the current year details, cutoffs, and aid stations before you commit. Race logistics change year to year.
The course runs along Millerton Lake and the San Joaquin River through Sierra foothill terrain in Fresno County, starting and finishing at the S. Finegold Picnic Area off Sky Harbor Road in Friant.
San Joaquin Running, also known as San Joaquin Trail Runners, is the same independent local club that puts on the historic Shadow of the Giants 50K, a well-regarded event among California ultrarunners. That pedigree carries into this race's course marking, aid station support, and general organization.
Aid stations are spaced roughly every 5 miles along the course, stocked with water, sports drink, gels, fruit, and basic first aid. Crew can meet 50K runners at the San Joaquin River Gorge Management Area near the Ya Gub Weh Tuh Campground, around mile 14.5 to 16.5, and that same area accepts marked drop bags.
The 50K allows pacers starting at mile 16, right around the San Joaquin River Gorge aid stations. If you plan to use one, that is your handoff point, and it lines up well with the back half of the race where fatigue and weather typically start to matter more than fresh-legs pacing.
From a 6:30 AM start to a 5:30 PM cutoff, the 50K gives you 11 hours, about 21 minutes per mile on average for a generous pace budget most trained ultrarunners can work with.
Sierra foothill trail like this rewards runners who adjust effort with the terrain rather than trying to hold one flat pace. A grade-adjusted pace target lets you run the downs a bit harder and the ups a bit easier, which usually nets a faster, more sustainable overall time than fighting the rolls with a single target pace.
A vert-aware finish-time projection built from your training gives you an honest number to check against the 5:30 PM cutoff well before the back half of the race. With 11 hours on the clock most runners have a comfortable buffer, but confirming that early lets you relax into your pacing plan instead of doing cutoff math on tired legs.
⏵ Free tools to pace this course
Early December here can run cool and damp or mild and sunny, and either way a 6:30 AM start means several hours of cooler morning conditions before things potentially warm up.
Aim for 50 to 70 grams of carbohydrate per hour, and use the roughly-every-5-mile aid station spacing to keep your intake steady rather than front-loading it early. That spacing makes this an easier course to fuel consistently than races with longer gaps between support.
Keep sodium in the 400 to 600 mg per liter range as a starting point, and adjust upward if December turns out warmer or sunnier than the typical foothill forecast. Cooler, damp days call for less; a clear, mild afternoon calls for more.
⏵ Build your fueling plan
Get a carb, sodium, fluid, and caffeine plan per hour built for your weight, your goal time, and a Central Valley December 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 San Joaquin River Trail course profile, and your projected splits, so race day is something you execute, not guess at.
It runs through the Sierra foothills along Millerton Lake and the San Joaquin River, terrain that rolls rather than punishes, with an 11-hour cutoff that gives most reasonably trained runners real room to finish. The bigger variables here are the December weather in the Central Valley foothills and the trail's exposure, more than a single defining climb.
The official race materials do not publish a total elevation gain figure for the 50K, so no specific number is stated here. Expect the rolling foothill terrain typical of the Sierra foothills above Millerton Lake, with repeated moderate climbs and descents along the river canyon rather than one sustained mountain ascent.
With an 11-hour window from a 6:30 AM start to a 5:30 PM cutoff, most 50K finishers are out for 6 to 10 hours. Aim for roughly 50 to 70 grams of carbohydrate per hour, and keep sodium in the 400 to 600 mg per liter range, adjusting upward if December in the Central Valley foothills turns out warmer than expected. Aid stations roughly every 5 miles give you frequent chances to refill rather than carrying everything from the start.
The published cutoff is 5:30 PM at the finish line, which from a 6:30 AM 50K start gives you 11 hours to cover the full distance. That works out to about 21 minutes per mile on average for a 31-mile course, a generous pace budget for most trained ultrarunners, though the rolling foothill terrain and any December weather should factor into how much of that buffer you actually plan to use.
The course runs along Millerton Lake and the San Joaquin River through Sierra foothills terrain in Fresno County, a mix of rolling trail with river and lake views. Early December in the Central Valley foothills tends to run cool and can be foggy or damp, occasionally sunny and mild, so check the specific forecast close to race day and be ready for either.
Yes, pacers are allowed for the 50K starting at mile 16, at the San Joaquin River Gorge area where Aid Stations 3 and 4 sit. That is roughly the midpoint of the race, so a pacer can help you manage the back half where fatigue and any weather changes are most likely to affect your pace.
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<a href="https://runsummitline.com/guides/san-joaquin-river-trail-50k">The San Joaquin River Trail 50K course guide</a><iframe src="https://runsummitline.com/embed/race/san-joaquin-river-trail-50k" style="width:100%;max-width:420px;height:180px;border:0;" loading="lazy" title="San Joaquin River Trail 50K 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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