Bynum is an unincorporated community and census-designated place in Teton County, Montana, United States, approximately 13 miles north of Choteau. Its population was 31 as of the 2010 census. Bynum is the site of a one-room country school, a general store, post office, an agate shop, and Two Medicine Dinosaur Center, which provides displays and educational programs about dinosaurs. The town's name is derived from the surname of a family of early settlers in the area. The post office was established in 1885. In 1908 work on the began.