Diablo Lake in Seattle 2025

Situated in the North Cascade mountains of Washington state, Diablo Lake lays between Ross Lake and Gorge Lake on the Skagit River at the height of 1,201 feet (366 m). The lake is part of Ross Lake National Recreation Area and is a popular camping, hiking, kayaking, and fishing destination. Rainbow, coastal cutthroat, brook, and other trout species live in this lake. The lake is famous for its turquoise water color as well. The water stays freezing even during the summer due to glacial waters. Diablo Lake's best season for hiking and water sports runs from May through September (late May to early September for camping).

Camping on Diablo Lake is possible with a permit. There are three boat-in camping sites on Diablo Lake. There is also a Colonial Creek Campground on State Route 20.

Diablo Lake Trail is a 7.5 miles long, starting at the North Cascades Institute parking lot. It begins not far from Marblemount, Washington, and features mild elevation gain of 1500 ft (457 m). The trail goes through rocky fields, rain forest-like areas, and dry open plains. Hikers pass talus slopes of Sourdough Mountain, waterfalls, and enjoy beautiful views of Pyramid, Ross Lake, Snowfield, Davis Peaks, and Jack Mountain.

The trail goes straight to the suspension bridge at Ross Dam, but the path down to the bridge is rather steep, so if you are hiking with dogs and children, it might be better to stay by Diablo Lake and enjoy its beautiful vistas.