From I-5 in Salem, take Exit 253 and head east on Hwy. 22 for 30 miles. In the town of Gates, turn right on Horeb Road, and in 0.1 mile turn left on Sorbin Street. Continue through Gates for 0.3 mile and turn right on Gates School Road. Go 1.1 mile and turn left on Henness Lane. Where the road turns to gravel the name changes to Monument Peak Road, and you’ll see the Monument Peak Road day-use parking area on the right. Continue 1.1 mile and turn right on Christmas Tree Road, then drive 0.5 mile to the campground.
This is a really fantastic and recently-reopened horse camp in Santiam State Forest. We just stayed for a night on 7/30 and found it to be really nicely set up in many ways. There's plenty of privacy between sites, well-established trails between and around the campground, and very easy access to tons of different trails. The maps they provide are easy to read and the signage is clear. The corrals are made with beefy 10-inch round logs with just enough space for our horses to comfortably move around.
This will be on our short list of places to horse camp. The only minor drawback is that the haul-in route is over gravel forest road, which can be steep and skinny in places. I'd recommend 4X4 trucks to be used for hauling more than 2 horses in.