Irvine Ranch Open Space Ultra Distance Hike: Fremont to Sierra Peak

The Irvine Ranch Open Space Ultra Distance, series is designed for experienced hikers who thrive on long days, big climbs, and the satisfaction of pushing physical and mental limits. This hike covers approximately 18 miles with 3,400 feet of elevation gain, traversing some of the most rugged and remote sections of the Irvine Ranch Open Space. This route combines steep ascents, rolling ridgelines, and exposed terrain with panoramic views that make every step worth the effort.

This is not a casual stroll — it’s a test of endurance, pacing, and preparation. Participants should have prior experience with strenuous, half-day or full-day hikes and be comfortable navigating challenging terrain in varying conditions.

Self-Sufficiency is Required There are no water sources, food stations, or supply drops along this route. Every participant is responsible for carrying all the gear, water, and nutrition they will need for the day. We strongly recommend: Water: Minimum 70 oz per person (more in hot weather) Food/Snacks: High-calorie, easily portable items to sustain 7 hours of hiking (energy bars, trail mix, sandwiches, electrolyte chews) Gear: Closed-toe hiking shoes or boots, sun protection (hat, sunglasses, sunscreen), extra layers, basic first-aid kit, trekking poles (optional but recommended) Under-prepared participants may be denied access to the hike.

Pace & Timing Expect to be on the trail for 7 hours, with extended climbs and limited shade. A steady, sustainable pace is critical. We will take short breaks as needed, but hikers should be able to maintain consistent forward progress throughout the day.

Important Notes This hike is physically demanding and not suitable for beginners. There will be no early exit points — once you commit, you must be prepared to complete the route. Weather conditions can greatly affect difficulty. Hot days will make the climbs especially punishing; cold or wet weather can increase risk and exposure. If you’re ready for a true challenge, breathtaking views, and the camaraderie of fellow Sufferfest enthusiasts, join us for the Irvine Ranch Open Space Ultra Distance Hike — and earn every mile the hard way.