Willow Creek is a long tributary of the Snake River in the U.S. state of Idaho. Beginning at an elevation of east of the Blackfoot Mountains in southeastern Bingham County, it flows generally north into Bonneville County and past Bone. South of the town of Ririe, the creek is impounded by Ririe Dam, forming Ririe Reservoir. It then turns southwest, passing between Iona and Ucon, before bifurcating into two distributaries, North Fork Willow Creek and South Fork Willow Creek, at an elevation of . Both forks reach the Snake River north of Idaho Falls.