Leslie Gulch is a canyon valley in southeastern Oregon on the east side of Owyhee Lake, known for abundant volcanic tuff formations that create a sharply sculpted, rugged landscape. Once called Dugout Gulch, it was renamed for local rancher Hiram E. Leslie, who was struck by lightning there in 1882. The area is managed by the Bureau of Land Management and includes boating and camping access, though roads and water levels can limit use. Leslie Gulch is also ecologically important, with endemic and rare plants, a bighorn sheep herd established in 1965, and other wildlife. Its cliffs have made it a regional climbing destination, though some route development sparked controversy.