An aerial view of Hyalite Reservoir and a view looking south down the line of the Gallatins that extends into Yellowstone Park. The Custer-Gallatin National Forest is one of the most visited national forests in the country and Hyalite Reservoir south of Bozeman is the busiest recreation complex on the forest. The Gallatin Forest Partnership anticipates that under its plan the Porcupine-Buffalo Horn could generate use levels as intense as those on trails near Hyalite.