Wildside Trail-De Leo Wall

Who was “De Leo” and why does he have a wall? The “wall” refers to an ancient extrusion of andesitic magma, which formed a ridge or rock “wall” that has resisted the grinding of glaciers and erosion and stands above the surrounding clay, sandstone and coal layers to the north. The De Leo’s were one of the first pioneer families to settle in the area. Their exploration of the area likely resulted in the wall being given the family name.

Stop at the information kiosk at the trailhead and pick up one of the free trail maps provided by King County Parks and Recreation. The map will guide you through the multitude of trails in the park as well as keep you safe and away from any hazardous areas.

Start your hike at the trailhead by choosing the Wildside trail (W1) and travel the short distance to the junction with the Bagley Seam Trail (W10). Turn right, staying on the Wildside Trail and crossing the bridge over Coal Creek. Soon you will reach the Rainbow Town Trail (W3) following it to the left for about 50 feet to where it re-joins the Wildside Trail. The Wildside Trail then continues along a path between the edge of the park to the west and Coal Creek to the east until it meets the Marshall’s Hill Trail (W6) at the base of Marshall’s Hill.

Turn right onto the Marshall’s Hill Trail and make your way up several gentle switchbacks. Note that as you climb the side of Marshall’s Hill that the forest changes from primarily salmonberry, maple and alder to hemlock, then mixed conifers. You will also see the outlines of suburban homes through the trees on the right as the trail follows the western border of the park. A number of neighborhood trails join W6 from the right, but you will want to continue straight ahead.

About 1.0 mile after joining the Marshall’s Hill Trail you will cross a service road and soon after intersect with the start of the De Leo Wall Trail (W9). Take this trail steeply up to the top of the ridge (Wall) for another 0.2 mile where a sign points to a steep, unmaintained boot path down to the De Leo Wall “viewpoint”. Note that this “viewpoint” is on private property outside the boundary of the Regional Park — it's not recommended to hike on this section. 

The official trail continues straight ahead before making it’s way down from the ridge top where you rejoin the Wildside Trail (W1) by turning left at the trail intersection. Follow the Wildside Trail along the wetlands and once past the junction with Marshall’s Hill Trail, simply retrace your earlier path back to the trailhead.

Trailhead facilities include portable toilets, picnic tables and an information kiosk with detailed park maps. There is no potable water in the park due to proximity to abandoned mining operations.

WTA Pro Tip: All official trails in the Cougar Mountain Regional Wildland Park are numbered. The letter prefix indicates the area of the park where the trail is located. N=north, S= South, E=East, W=West and C=Central.