Summit Ridge Loop is a 6.3 mile loop trail located near Black Diamond, WA that features a river. The trail is rated as moderate and primarily used for mountain biking.
Just so everyone knows, Summit Ridge is primarily for mountain biking. You can hike, and even ride horses in some areas, but it the trails were designed with mountain bikes in mind. Summit Ridge is connected with Henry's Ridge, which is also a mountain biking area, but is more hiker and horse friendly.
Summit Ridge is awesome for new and experienced mountain bikers. It features a downhill freeride section with different difficulty levels, as well as several long technical trails through the forest. All of it is very well made and well maintained for the most part.
I went to the location on the map, and found some developing paths - one bisected by railroad tracks. on the hill side I found a few obnoxiously half baked downhill trails that could be really good if worked on, but are only good for breaking your neck ad/is. To get to this death trap, take the hill side trail to some undeveloped rough stone road under crackling power lines that are overgrown with scotch broom and black berry vines. Ride around the loop and look for the occasional trails jetting off here and there.
Warning, on top you can easily loose what trail you rode up, a marker is needed.
I took my little brother and daughter for a hike. Wasn't crowded, but it was a week day. The trails are really set up for mountain biking with a lot of turn offs and loops. Good trails to explore for easy hiking, and excellent runs for mountain bikes. The trail we were on was a black Diamond with a lot of bike bridges. I didn't get to check out the other trails.