Drive Idaho Highway 75 38.6 miles east of Stanley, ID and take a right (south) on the East Fork Road, where the east fork of the Salmon River joins the main channel of the river.
Continue 17.8 Miles from the highway and turn off onto Big Boulder Creek Road (FS 667)
4.2 miles to the west you will park at the trailhead just past Livingston Mill.
Take the Big Boulder Creek Trail (FT 680) about a mile in, and turn left onto the Livingston Mill/Castle Divide Trail (FT 047) which takes you up over a ridge and down towards the Boulder Chain Lakes. This is a great place to camp if you are on a 3+ day trip. Continue on FT-047 until an intersection with FT-684. You will not take FT-684, but instead look for a trail running northeast through the trees. Once you clear the trees look for a path running north that will lead you to lake 9419 (Castle Lake).
From Castle Lake, come around the north side of the lake to the base of a small headwall on the west side of the lake. Here there is a small section of class 3 scrambling to get to the main basin and gully runout for the big gully of Castle Peak. This may be the most technically difficult section of the climb, and there are many routes up. Use your eye for route finding and find a way up through the ledges and cliffs.
|Scramble up this small headwall.|Now, head towards the gully.
Once you've reached the top of the headwall head south toward the big gully. You'll do a lot of boulder hopping before you reach the base of the gully. A word of caution: look and see if there is anyone else on the route ahead of you. If there is another party, it would be a good idea to wait for them to clear the route before heading up. One small rock can trigger a massive cascade of rockfall on this route, one of the many dangers of the big gully.
Big Gully from Merriam Big Gully en route
Once you reach the base of the big gully, aim for the obvious notch and start heading up. If you find yourself questioning, "which notch?", it's the one on the right. Snow conditions may vary, and could linger in the gully well into late summer which will change potential route options. If the upper portion of the gully is melted out, solid rock along climber's right of the main gully can be found. The rock quality is better than you might expect if you've heard any of the "horror stories" about loose rock on the big gully route. The major danger here is the steepness of the route combined with little if anything to stop a rock should it begin to fall. If you've done any scrambling you have inevitably stepped on a small boulder or large chunk of talus and had it tilt, slide, or tumble a short distance before coming to a rest. Well on this route, if you knock anything lose chances are it's going to keep going all the way to the bottom possibly causing other rocks to break loose and join it on the way down. Be careful. If you are in a party stick close together. Try not to step on any boulders that seem to be resting alone, but rather place your feet on the more solid rock which is firmly embedded in the mountain. As mentioned, there is good quality rock on the route, just avoid the loose stuff.
Avoid loose rocks (bottom left) and stick to solid rock.
As you near the top, the summit will be to the right of the main notch. If you've been scrambling up the section of rock to the right of the main gully you will encounter steepening terrain as you near the top. You may need to traverse left towards the notch unless you can find a route up from where you are at. Once at the notch, the hard part is over and it's just a short section of boulder hopping until you're on the summit of Castle Peak!
Helmet! Even you you stick to the philosophy of "safety first" you still may encounter falling rock. Helmets are highly encouraged.
Early season climbs may require crampons and axe.
This route is almost always done as an overnighter of at least one night. Castle Lake is the optimum place to stay. It is secluded and you'll likely have the entire area to yourself. Other options would be any of the Boulder Chain Lakes or possibly Noisy Lake or Quiet Lake.
Perfect spot to camp? Yes, I think it is... Sunrise at Castle Lake.