Union Mountain is a remote 7,601-foot summit in Montana’s Flathead Range, within the Great Bear Wilderness and Flathead National Forest. Rising steeply above the Middle Fork Flathead River, it has striking local relief, climbing about 2,800 feet in roughly 1.5 miles. Runoff from the mountain drains north toward the river, and Capitol Mountain is the nearest higher peak. The nearby Schafer landing strip, preserved when the wilderness was designated, continues to provide access for backcountry visitors. Union Mountain has a subarctic climate with long, bitter winters and short summers. Its sedimentary rock formed from the Precambrian through the Jurassic, and its broader landscape was shaped by the Lewis Overthrust fault.