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⏵ Course guide · Free

American River 50 Course Guide

The AR50 is one of the fastest, most popular 50 milers in the country, a point-to-point from the Sacramento Valley up into the Sierra foothills at Auburn. It opens on a fast paved bike path, then switches to rolling singletrack on the Cal Street section, and it finishes with a real climb to the line. I will walk you through the whole course, then give you pacing and fueling beta built for exactly that shape, plus free tools to dial in your own numbers.

⏵ Quick facts

The AR50 at a glance

Date
Sat, April 3, 2027 (annual, early April)
Location
Sacramento Valley to Sierra foothills, CA
Start / Finish
Folsom Point (near Folsom) to Overlook Park, Auburn
Distance
50 miles (also 25 mile and shorter options)
Elevation gain
About 5,403 ft of gain, about 4,530 ft of loss
Terrain
Early paved bike path, then rolling singletrack trail
Time limit
14 hours (6:00 AM start, 8:00 PM finish cutoff)
Qualifier
Western States Endurance Run qualifying race

Note: the AR50 runs every year in early April, and the next edition is Saturday, April 3, 2027. The start area, exact aid mileages, and intermediate cutoffs can move around year to year, so always confirm the date, the route, and the cutoffs on the official AR50 site before you plan your race.

The course

The AR50 is a point-to-point. It runs from Folsom Point near Folsom, up the American River corridor, and finishes at Overlook Park in Auburn. You get about 5,403 feet of climbing and about 4,530 feet of descent across 50 miles, which by ultra standards makes it a fast, runnable course, with no one big mountain climb and most of the gain saved for the second half.

The bike path: fast, flat, and a trap

The gun goes off at 6:00 AM, and for most of the first roughly 19 miles you are on a paved bike path running along the American River. It is fast and it almost feels like a road race, with smooth pavement and gentle grades. Your legs are fresh and it is dangerously easy to lock into a road pace and bank what feels like free time. Do not.

The discipline here is to treat the bike path like a controlled warmup, not a PR attempt. Hold an effort that honestly feels too easy. The runners who finish strong are almost always the ones who got off the pavement still feeling fresh, because the back half of this course is where the real work and the real climbing are.

The Cal Street section and the rolling trail half

After the bike path it is trail the rest of the way, with rolling singletrack along the river through the Cal Street section. This is where the AR50 stops being a fast road-style effort and becomes a true trail ultra. The footing gets more technical, the grades roll, and the aid stations sit farther apart, including a long stretch in the early trail miles where you go a good while between support.

Pace this half by effort, not by the clock you saw on the pavement. Your minutes per mile will slow down on the rolling trail, and that is fine, that is supposed to happen. Keep eating and drinking the whole way through here, because the closing climb is still out there and you do not want to show up at the bottom of it already empty.

The closing climb to Auburn

The AR50 finishes with a real climb, roughly 2.4 miles up to Overlook Park in Auburn. After 47 or so miles, this final grind is where the race is decided. Runners who spent too much on the early bike path get here with nothing left, and the climb turns into a long, demoralizing power hike against the clock.

So save something for this. If you ran the front half with some restraint, the climb to Auburn is a strong, satisfying close instead of a survival march. And practicing climbing on tired legs in training pays off right here.

Aid stations, weather, and cutoffs

The course has a series of aid stations with water, electrolyte drink, soda, ice, and food, and there are drop bags and crew access at the major checkpoints listed on the official pace chart. Just be ready for at least one long stretch between aid in the early trail miles, and carry for it. April in the Sacramento Valley and Sierra foothills is usually mild, but it can swing from cool and damp to genuinely warm, so plan your fluid and sodium off the forecast, not off some average.

The overall time limit is 14 hours, a 6:00 AM start to an 8:00 PM finish cutoff, which is roughly a 16:48 per mile average. That is generous. But there are intermediate cutoffs along the way, so check the official AR50 pace chart for the current edition and build your plan backward from those times, with a buffer left for the closing climb.

Pacing strategy for the AR50

A fast course with a back-loaded profile pays you back for being patient early and strong late. Pace the bike path by effort, not by the road splits it tempts you into, and save your legs for the trail and the climb.

Bank effort, not time, on the bike path

The single most common AR50 mistake is running the early pavement too hard because it feels effortless. Resist it. Run the bike path at an effort that feels conversational and a little lazy, and let the faster runners go. You are not trying to win the first 19 miles, you are trying to get to the trail with fresh legs and a stomach that is still happy.

Use our free grade-adjusted pace calculator to turn your flat fitness into honest effort targets, so you actually know what a sustainable bike-path pace is for a 50 mile day instead of a road race.

Set a realistic finish goal that accounts for the trail half

It is tempting to take your finish straight off those fast early miles, but the rolling Cal Street trail and the closing climb are going to slow you down, and a goal built off the flat just leaves you chasing a time you cannot hit late. Build your target around two paces instead, a quick one for the pavement and a more honest one for the trail and the climb.

Use our vert-aware race time calculator to fold the climbing and the trail into one realistic projection, then check that against the AR50 cutoffs so your plan has margin built in for the climb to Auburn.

Reality-check your goal before you commit

If you are coming into the AR50 off a road marathon or a shorter trail race, your raw fitness might not carry over the way you think it will to a fast 50 miler with a back-loaded climb. Figure that out before race week, not in the middle of the race.

Our race equivalent calculator helps you reality-check your 50 mile goal off a recent result, so you toe the line with a number you can actually run instead of a hopeful one the closing climb is going to expose.

Fueling strategy for the AR50

A fast course means a high, steady carbohydrate burn for hours, and the long gaps between some aid stations mean you have to carry and manage yourself. Fueling discipline is the thing that keeps the back half from falling apart.

Carbs: keep the engine fed at a fast pace

Because the AR50 stays runnable, you burn carbohydrate at a real clip the whole day, so aim for roughly 60 to 90 grams of carbohydrate per hour, and lean toward the high end once your gut is trained to take it. Use a glucose-plus-fructose blend so you can absorb more than a single sugar lets you, and rehearse your exact hourly number on long runs so on race day it is routine, not an experiment.

And do not let the fast early pavement trick you into under-fueling. The hours add up, and a calorie hole you dig on the bike path shows up later as a fade on the Cal Street trail and a crawl up the closing climb.

Sodium and fluid: carry for the long gaps

There is at least one long stretch between aid stations in the early trail miles, so carry enough fluid and electrolytes to cover it instead of rationing. Bias your sodium toward 500 to 700 mg per liter of fluid, and push it higher if April turns warm in the Sacramento Valley, because cramping and a sloshy, wrung-out stomach late in a race are almost always fluid and sodium balance problems, not fitness problems.

Dial in a personalized plan with our free ultra fueling calculator. Put in your weight, your goal time, and the conditions you expect, and it hands you a carb, sodium, fluid, and caffeine prescription per hour built for the AR50 duration. Then go test it in training.

⏵ Free calculators for this race

Run your AR50 numbers with our free, no-signup tools, then let Summit Line tie them all back to your real fitness and this exact course.

See all free running tools →

Train for the AR50

The AR50 pays off a specific kind of prep: the durability to run fast for hours, the discipline to fuel while you are moving, and enough climbing-on-tired-legs work to handle the climb to Auburn. These free guides cover the parts that matter most for this course.

⏵ Train for the AR50

Get a race-day plan dialed to YOUR fitness, this exact course profile, and your projected splits. Summit Line reads your actual training, builds a fueling and pacing plan around the fast AR50 bike path, the Cal Street trail half, and the closing climb to Auburn, and tracks how your gut and legs handle the load, so race day is rehearsed instead of guessed.

Get started free →See it on a real race plan

American River 50 FAQ

How hard is the American River 50 (AR50)?

By ultra standards the AR50 is fast and runnable, and that is exactly the thing that humbles people. The first roughly 19 miles follow a paved bike path along the American River, your legs are fresh and it is so easy to run too hard, and then the back half flips to rolling singletrack on the Cal Street section before a closing climb of about 2.4 miles up to the Auburn finish. There is roughly 5,400 feet of total climbing across 50 miles, so this is way gentler than a mountain ultra. But the runnability is the trap. Most people who blow up here do it by banking time on the early pavement and then paying it all back on the trail. It is a Western States Endurance Run qualifier and one of the largest 50 milers in the country, so finishing it strong actually means something.

How much climbing is in the AR50?

The official course lists about 5,403 feet of gain and about 4,530 feet of loss across the full 50 miles. There is no one big mountain climb. The gain comes from rolling trail in the second half plus a closing ascent of roughly 2.4 miles up to the Overlook Park finish in Auburn. Next to a high-mountain hundred miler that is not much vert. But it shows up late, when your legs are already deep into the day, so the climbing is brutal on anyone who spent too much on the flat early miles.

How should I fuel for the AR50?

Fuel it like a long day where the pace never really backs off. Most runners aim for roughly 60 to 90 grams of carbohydrate per hour, and you can lean toward the high end once your gut is trained for it, because this course stays runnable and you keep burning carbohydrate at a real clip the whole way. Your sodium and fluid needs go up if the Sacramento Valley turns warm in April, so a sodium concentration around 500 to 700 mg per liter of fluid is a sensible starting point, and push it higher in the heat. There is a long stretch in the early trail miles where aid is spread out, so carry enough to get between stations. Our free ultra fueling calculator builds you a personalized carb, sodium, and fluid plan per hour for your expected finish time and the conditions.

What are the AR50 cutoffs?

The overall time limit is 14 hours, from a 6:00 AM start to an 8:00 PM finish cutoff, which works out to roughly a 16:48 per mile average across the whole course. For a 50 miler that is generous. But there are intermediate cutoffs at points along the route, and the official AR50 pace chart for the current edition lists each one along with drop bag and crew access. The closing miles include a real climb to Auburn, so build your plan with a buffer and do not leave yourself racing the clock up that final ascent.

Is the AR50 a flat road race or a trail race?

It is both, in two pretty distinct halves. For most of the first roughly 19 miles you are on a paved bike path along the American River, and it runs fast and almost like a road race. After that it is trail the rest of the way, with rolling singletrack through the Cal Street section and a closing climb to the Auburn finish. The smart move is to treat the bike path like a controlled warmup, not a chance to set a road PR, so you still have legs for the trail half where the race is actually decided.

Does the AR50 count as a Western States qualifier?

Yes. The American River 50 Mile Endurance Run is a recognized Western States Endurance Run qualifying race. Finish inside the official cutoff and you have a qualifier on your record for the Western States lottery. That qualifier status, the fast runnable profile, and the big field are a large part of why the AR50 is one of the most popular 50 milers in the United States.

This guide is for planning and training purposes and reflects publicly available information about the American River 50 Mile Endurance Run. Race details, including the date, exact course, aid stations, and cutoffs, can change year to year. Always confirm the current specifics on the official AR50 race website before you train or travel.