Tucked in a narrow canyon between the more famous Yellowstone and Madison rivers, the Gallatin River flexed its persona in the mid-1990s when the movie “A River Runs Through It” was filmed near Storm Castle. The Gallatin begins in the northwest corner of Yellowstone before knifing through the Madison and Gallatin ranges en route to forming the Missouri. It is a fine trout stream in its own right and, in its lower stretches, features one of the most important cottonwood riparian areas remaining in Montana.