The Olallie Trail in Olallie State Park is a new (as of Fall 2017) trail dedicated to mountain bikers, but open to all forms of non-motorized recreation such as hiking and horseback riding. It takes recreators up the slopes of Mount Washington above the I-90 corridor. Stop at multiple viewpoints on your way up that look north across I-90 towards the rest of the Mt. Baker-Snoqualmie National Forest.
Olallie State Park protects a section of the South Fork Snoqualmie River right along I-90. There are a number of trails in the park that take you to waterfalls and over creeks. It also connects with the Iron Horse Trail. This is how you reach the Olallie Trail, and there are a few places to start from. You can start at the Cedar Falls trailhead, which is near Rattlesnake Lake. Walk about two miles east along the Iron Horse Trail until you reach the junction with Olallie. Or, you can start from either Twin Falls trailhead in Olallie State Park and connect to the Iron Horse Trail.
Once you have walked the Iron Horse Trail and reached the junction, turn south to hop onto the Olallie Trail. The trail is in excellent shape. Because it was designed for mountain bikers, it is a pleasant hike for hikers due to the comfortable grade. Many of the turns are banked to provide comfortable riding to mountain bikers. Climb through switchbacks, winding your way up Mount Washington. There are seven designated viewpoints along the trail, with views of Mt. Si, Little Si, the Mountains to Sound Greenway, Mailbox, Bessemer, and various other peaks along the I-90 corridor.
The Olallie Trail also provides access to a trail to the top of Mount Washington. This trail is only available for hikers and splits off from the Olallie Trail at about 6 miles. The Olallie Trail continues east for another 3.2 miles towards Change Mountain, where it ends. Make your way back through the forest, a pleasant descent for bikers after the climb up. This trail is a great option for hikers looking for a longer hike to who don't mind seeing the occasional biker or equestrian. For bikers and equestrians, it's a great option because of the great condition of the trail and plenty of viewpoints to stop at and enjoy the view.