Boulder River (Sweet Grass County, Montana)
A section of the upper Boulder River
|Basin countries||Park and Sweet Grass County, Montana|
|Mouth elevation||4,003 feet (1,220 m)|
|River system||Yellowstone River|
It rises in the Gallatin National Forest in the Absaroka Range in southern Park County. It flows north through mountainous canyons, a cataract under a natural bridge, and northwest in a widening valley past McLeod. It joins the Yellowstone at Big Timber. The landscape of the Boulder River and river valley has merited the filming of two movies: A River Runs Through It and The Horse Whisperer.
The river is a popular destination for fly fishing. Other attractions in the valley include several church camps, a guest ranch, and several USFS campgrounds. The Forest Service also maintains several guard stations, trailheads, and picnic areas in the valley.
The Boulder River has also been known as: Rivers a Cross, Rivers across, and Rivers-across.