About this spot
Deep Lake sits in Sun Lakes-Dry Falls State Park, about 3 miles west of Coulee City off WA-17; look for the separate Deep Lake access road inside the park (Discover Pass required). Ice Age flood-carved basalt cliffs line the northwest shore, from 5-foot ledges up to a well-known ~30-foot jump, with a lakeside trail letting you size up smaller drops before the bigger ones. Jumping isn't officially sanctioned by the park but is widely practiced. The basalt footing is uneven and slick, and underwater ledges near the base of the taller cliffs have caused injuries — clear the rock before committing to a line.
Safety first. Cliff jumping is inherently dangerous and can cause serious injury or death. Conditions — water depth, submerged hazards, and access — change constantly. CliffScout is community-sourced reference information, not a guarantee a spot is safe. Always assess the conditions yourself before jumping, and never jump where you're unsure. You assume all risk.