Mt Si Relay & Trail Runs

Event Overview

The Mt Si Relay & Trail Runs is set for Sunday, May 4, 2025, in Snoqualmie, WA. Registration will close on May 2 at 11:59 PM PT. This event includes:

• 50-Miler
• 50K
• Marathon
• Half Marathon

Solo Distances

For those not ready for an ultra, both the half and full marathon offer excellent options with generous course cutoff times. The half marathon will provide 6 aid stations, while the full marathon includes 8 aid stations along the way. This venue is perfect for runners stepping up to a 50K or 50-mile distance for the first time.

Relay Challenge

New to relay races? The Mt. Si Relay is designed for ease, accommodating both novices and seasoned teams. Each relay team consists of five members, where each member runs two legs of 3-8 miles. Team categories are organized by total age on race day, allowing flexible team assembly.

Course Description

The course runs on the Snoqualmie Valley Trail and John Wayne Pioneer Trail, offering breathtaking views. The 50-Mile course features a mix of rural roads and trails, with 12 aid stations. The half marathon and marathon runners share the initial route with 50K runners, turning around at the midpoint.

Event History

This event has a rich history, starting in 1983 as the “Falls to Gasworks Relay.” It was renamed and restructured in 1999, evolving into the Mt. Si Relay & Ultra Run.

Start Times

• 50-Miler: 6:00 AM
• 50K: 8:30 AM
• Marathon: 9:00 AM
• Half Marathon: 10:30 AM