The Stillwater River flows through Park and Stillwater Counties in south central Montana, originating high in the Absaroka-Beartooth Wilderness near the Yellowstone National Park boundary and Wyoming state line before joining the Yellowstone River. Despite its name, this river is anything but still—characterized by swift, rocky waters that tumble through dramatically varied landscapes. From its mountainous wilderness headwaters, the Stillwater transitions through rolling plains and ranch lands of the Stillwater Valley, offering over 70 miles of diverse fishing opportunities. The river supports high trout densities of approximately 3,000 fish per mile and remains relatively lightly fished compared to nearby famous waters, providing anglers with quality fishing experiences amid stunning Absaroka-Beartooth Mountain scenery. Its freestone character produces cold, clean water that maintains excellent fishing conditions when other rivers may be too warm or low during summer months.