Marion Mountain to San Jacinto is a 11.2 mile moderately trafficked out and back trail located near Idyllwild, CA that features a river and is only recommended for very experienced adventurers. The trail offers a number of activity options and is accessible from June until October.
Full Day hike! Definitely separates the avid from the casual hikers, this is one hike you want to be acclimated for, or allow extra time to reach the peak. Calories and water count. If there's a hint of bad weather, make sure you are prepared for it with at least a windbreaker and 10 essentials. Even though I have never seen a ranger on any trail in Southern California, you need to get a permit to enter the San Jacinto Wilderness. Get it from the station in Idyllwild. If you can't get a permit for the hike, Marion Mountain Campground might be a way to sideline the 9 to 5 type restriction on permitting. If you get a campsite pass, you are supposed to be able to hike the Forest as well. You will still need a State pass for the area after about a mile and a half on the trail going up the mountain... Get both, or just stay at a campground and then get the State pass. There are several routes up San Jacinto. Most people take the Palm Springs Aerial Tram up from the desert floor and begin their journey in Long Valley. The lesser-travelled Marion Mountain trail skips the tram, beginning a few miles north of Idyllwild. It's the shortest route up Mt. San Jacinto. It's also steep, relentlessly climbing over 4,000 feet in under 6 miles.