03/25/2026
Run the Rim 2026 is fueled by Hammer Nutrition ⛽
📍 Arnold Rim Trail, Arnold, CA
🗓 May 31, 2026
Not every trail race takes you across an ancient lava cap. Welcome to the Arnold Rim.
With five distances from 5K to 50K, Run the Rim offers an adventure for every trail runner, whether this is your first time on the trails or you are a seasoned veteran. Frequent, well-spaced aid stations stocked with Hammer Nutrition products and generous cutoff times take the pressure off, and at a max elevation of 4,500 feet, you won't be fighting thin air. A legitimate introduction to mountain ultras, or the perfect early-season race to begin your altitude acclimation.
The point-to-point distances (50K, 35K) plunge in and out of three Sierra drainages before climbing to the ancient lava cap ridgeline known as the Arnold Rim at 4,500 feet with its dramatic views of Mt Diablo to the west and the Sierra crest to the east. From the Rim, singletrack continues through a cathedral forest of Ponderosa Pine, Sugar Pine, and Incense Cedar that has been growing since before California was a state. Punishing rocky descents, then sudden payoff, long, flowing stretches of pine-needle-carpeted trail so fast and soft you'll forget you've been climbing.
The 21K is a figure-8 loop through the same terrain, all the technical singletrack and ridge views, a self-contained adventure.
The 10K and 5K loop through the same magnificent mixed conifer forest on smooth, fast, and relatively flat singletrack around White Pines Lake, all the beauty, none of the vert. Every runner, regardless of distance, finishes at White Pines Lake. Jump in!
To learn more or register now, click the link: https://ultrasignup.com/register.aspx?did=135759
Arnold Rim Trail Association
