J Harlen Bretz (September 2, 1882 – February 3, 1981) was an American geologist, best known for his research that led to the acceptance of the Missoula Floods and for his work on caves. He was born to Oliver Joseph Bretz and Rhoda Maria Howlett, farmers in Saranac, Michigan, the oldest of five children. He earned a degree in biology from Albion College in 1905, where he also met his wife Fanny Chalis. Thereafter, he became interested in the geology of Eastern Washington state.