From big races to Saturday morning group runs—find ultra events and connect with the local endurance sports community.
April 4, 2026
Folsom to Auburn
Welcome to the legendary and historic American River 50 Mile Endurance Run, one of the oldest and most revered ultra races in the country. For decades, this race has tested the strength, endurance, and spirit of runners as they tackle a breathtaking journey from the heart of Sacramento to the rugged trails of Auburn, following the beautiful American River Parkway and offering iconic views of Northern California. If you're not quite ready for the full 50 miles, the American River 25 Mile and 10 Mile distances offer a fantastic way to experience the race's unique atmosphere and scenic routes. Both shorter distances provide a rewarding challenge while allowing runners to enjoy the same stunning landscapes and supportive trail community that make the American River races so special. Whether you're aiming for a new distance or looking for an introduction to endurance running, these races deliver the perfect balance of excitement, beauty, and camaraderie.
Entry includes
NorCalUltras Goody Swag Bag 👜
Technical Race Shirt 👕
Hand Crafted Finisher Medallion 🏅
Neversecond Gels on Course 🍭
Skratch Hydration on Course 🥤
Professional Timing and Results 🔍
Post Race Party 🎉
Nadia's Mac Shack 🍝
Beverages and Dust Bowl Beer Garden for those 21 and Over 🍻
Please visit American River 50 web site for detailed race information along with lodging opportunities in our host City of Folsom.
We look forward to seeing you on April 4th!
The NorCalUltras Team
The Jewel of the Sierra Nevada
November 7-8, 2026
Welcome to the 2026 Rio Del Lago Endurance Runs Presented by Altra!
🎉 Celebrating 25 Years of the Rio 100 & 5 Years of the Rio 50K!
The celebration is on! The Rio Del Lago Endurance Runs presented by Altra return on November 7, 2026, marking the 25th anniversary of the legendary Rio 100 Mile Endurance Run and the 5th running of the fan-favorite Rio 50K.
Whether this is your first Rio or your twenty-fifth, we’re doing cartwheels to welcome you to this milestone year. Together, we’ll honor a quarter century of endurance, community, and trail magic on one of Northern California’s most iconic courses.
🌄 About the Races
Rio 100 Mile Endurance Run presented by Altra
A true test of grit, determination, and heart. The Rio 100 takes runners on a breathtaking journey from Folsom to Auburn and back, showcasing miles of rolling singletrack, river views, and the rugged beauty of the Sierra foothills.
Rio 50K Endurance Run presented by Altra
Now in its 5th year, the Rio 50K starts alongside the 100 milers at Beal’s Point and follows the scenic early miles of the course. With stunning views along Folsom Lake, Lake Natoma, and the infamous Johnny Cash Trail, it’s the perfect distance for your first ultra or your fastest 50K yet!
🌟 A Milestone Year — A Legendary Experience
As we celebrate 25 years of Rio, expect an unforgettable weekend filled with tradition, camaraderie, and celebration. From world-class race organization and well-stocked aid stations to the warmth of our incredible volunteers, this year’s event will capture everything that makes Rio Del Lago truly special.
🎽 All Entries Include:
NorCalUltras Goody Swag Bag
Commemorative 25th Anniversary Technical Race Shirt
Finisher Medallion
100 Mile Finisher Belt Buckle (sub-30-hour finishers)
100 Mile Finisher Athleisure Lightweight Pullover
Neversecond Gels on Course
Skratch Hydration on Course
B-Tag Chip Timing
Bob and Brandt's Breakfast Bistro
Chef Tim’s “Soup for the Soul”
Beer Garden
🏕️ Plan Your Race Weekend
Visit our official website for detailed race information, course maps, and lodging options in our host city of Folsom, California.
💛 Join the Celebration
Be part of history as we honor 25 years of the Rio 100 and 5 years of the Rio 50K — a milestone weekend filled with tradition, community, and endurance.
25 Years Strong. 25 Years of Grit. 25 Years of Rio.
We can’t wait to celebrate this special year with you on the trails!
– The NorCalUltras Team