One of the most historically significant races on the US trail running calendar returns on Saturday 11 April as the Lake Sonoma Ultra Trail Festival is staged for the 16th time, and for the first time the signature 50-mile event is accompanied by a brand-new 100-kilometre distance. Run on the same trail network above the Warm Springs Dam near Healdsburg in California's Sonoma County, the event will also include the established 50K and the Trail Sisters Women's Half Marathon, with separate elite starts for the men's and women's 50-mile and 100K races and a full day of livestream coverage beginning shortly after the 6:30 AM race start. The addition of the 100K represents the most significant change to the Lake Sonoma format since the race rebooted as a TERREX-sponsored event following a brief hiatus.
The 50-mile course is unchanged and remains one of the more technical fifty-milers in the country. An out-and-back circumnavigation of the Warm Springs arm of Lake Sonoma, it is roughly 86 per cent single-track, 9 per cent dirt fire road and 5 per cent pavement, with approximately 10,500 feet of climbing and an equal amount of descending over the distance. The new 100K extends the course by adding an additional loop at the far end of the route, bringing total climbing to around 13,400 feet and taking elite competitors into the 9 to 10-hour range depending on conditions. The early weather forecast for Saturday is warm and dry — highs in the upper 70s Fahrenheit are predicted, which will put a premium on pacing and hydration discipline on an already demanding course.
The 50-mile elite field is as strong as any in the race's history. On the men's side, returning podium finishers Adam Peterman and Cody Lind are among the favourites alongside a formidable international contingent. The women's 50-mile race is equally stacked, with Keely Henninger, Rachel Drake and Abby Hall leading a field deep enough to break course records under favourable conditions. The inaugural 100K has drawn a more experimental entry list featuring several athletes stepping up from fifty-milers and others using the race as a final sharpening effort before Western States on 27 June. Lake Sonoma has long served as an informal qualifier and measuring stick for the Olympic Valley classic, and its late-April placement on the calendar reinforces that role.
Race director Tim Tollefson has leaned into the event's hybrid character as a serious competitive race and a community festival. The race village at the Warm Springs Dam launch area includes an expo, athlete panels, livestream viewing and an awards presentation on Saturday evening. A cash prize purse is paid to the top finishers in each race, continuing a tradition of professional prize structures that has become more common on the US trail scene over the last three seasons. Lake Sonoma also remains one of the few ultras in the country to provide live stream coverage on a scale approaching European trail races, with remote cameras positioned at key course checkpoints and commentary stitched together from multiple on-course teams.
The broader significance of Lake Sonoma in 2026 is partly about continuity and partly about reinvention. This is a race whose roots go back to 2008, whose early years helped shape the modern US ultra scene, and which carries genuine historical weight in a sport that can sometimes feel newly assembled. The new 100K is an acknowledgement that the distance has become the dominant competitive distance in global trail racing, driven by UTMB, Golden Trail and other international circuits. But the 50-miler remains the event's identity, and Saturday's race will be watched closely for what it tells us about the pecking order ahead of Western States and the summer's European trail season.