River's Edge Trail Race

River's Edge starts at the Katy Crossing trailhead, across the footbridge from San Gabriel Park in Georgetown, and the 50K runs the 10-mile loop three times. The trails hug the banks of the San Gabriel and link several parks together: hard-packed, flowing singletrack, shaded dirt roads and open fields, with punchy short climbs and, in the organiser's words, no sustained elevation gain. The loop is laid out as a figure of eight, so there is two-way traffic through San Gabriel Park.

The 50K goes off at 7:30 a.m., runners must be on their last lap by 11:30 a.m., and the trail course closes at 3:30 p.m., eight hours after the gun. The day then turns over to a cross-country mountain bike race on the same trails from 5:00 p.m.

Bridge is the start, the finish, the lap turnover and the only drop-bag point. Meadow is passed twice a lap, outbound at 2.6 miles and inbound at 9.6, with Rabbit Ears at 5.3. The race asks everyone to be able to carry water for up to five miles at a time.

Three laps of a 10-mile loop for the 50K; the 25K runs the 5-mile loop and then the 10. Aid at Bridge (start, finish, lap and drop bags), Meadow outbound at 2.6 miles, Rabbit Ears at 5.3 and Meadow inbound at 9.6. The race publishes no elevation figure, saying only that the terrain is rolling with short climbs and no sustained gain. Note the limit if you ran it before: the 2027 schedule closes the trail course at 3:30 p.m., eight hours after the 50K gun, where 2026 ran to nine and its last finisher came in at 8:56:05.

First-come sign-up on RunSignUp, with no lottery and no qualifying standard, and the 50K capped at 95 places. Entry for May 2027 opened on June 3, 2026 and closes at 9:59 a.m. on race morning. The 50K was $117 through March 1, 2027 and rises in steps to $142 by race day. The organiser expects it to sell out, and the cap has grown each year, from 75 in 2024 to 85 in 2025 and 95 since. May 4 is the deadline to be sure of a shirt, and there is no camping at this race.