The Boulder Mountains are a mountain range running roughly north to south located west of Boulder between Helena and Butte in the U.S. state of Montana.[1] Parts of the range are in four different counties: Deer Lodge, Jefferson, Lewis and Clark, and Silver Bow.[1]
Haystack Mountain, which reaches 8,819 feet (2,688 m), is the tallest peak in the range.[2][3] The three other highest peaks are Jack Mountain at 8,752 feet (2,668 m), Bull Mountain at 8,609 feet (2,624 m), and Thunderbolt Mountain at 8,597 feet (2,620 m).[2] All four peaks are in Jefferson County.[2]
Rocker Peak, 8,455 ft (2,577 m),[4] is near Jack Mountain (Montana), the second highest peak in the Boulder Mountains.[5] There is a SNOTEL weather station near the summit of Rocker Peak at an elevation of 8,000 ft (2,438 m). Rocker Peak has a subalpine climate (Köppen Dfc), bordering on an Alpine climate (Köppen ET).