Boulder Mountains (Montana)
The Boulder Mountains is a mountain range running north–south west of Boulder between Helena and Butte in the U.S. state of Montana. Parts of the range are in four different counties: Deer Lodge, Jefferson, Lewis and Clark, and Silver Bow.

Haystack Mountain, which reaches , is the tallest peak in the range. The three other highest peaks are Jack Mountain at , Bull Mountain at , and Thunderbolt Mountain at . All four peaks are in Jefferson County.