Box Elder is an unincorporated community and census-designated place (CDP) in Hill County in the U.S. state of Montana.

U.S. Route 87 passes through Box Elder, leading northeast 24 miles (39 km) to Havre, the Hill County seat, and southwest 10 miles (16 km) to Big Sandy.

According to the United States Census Bureau, the Box Elder CDP has a total area of 0.77 square miles (2.0 km2), all land.

4.9% of all households were made up of individuals, and 1.6% had someone living alone who was 65 years of age or older.

Box Elder Public Schools educates students from kindergarten through 12th grade.

Stone Child College is located 8 miles (13 km) east of Box Elder in Boneau.