Gibraltar Mountain, a 3,784-foot peak just southeast of Republic in northeastern Washington, is a prominent landform of the old Republic Mining District and a familiar landmark above the town. Set on the edge of the Kettle River Range within the Monashee Mountains, it was shaped by volcanic flows, faulting, erosion, and major glaciation that left rounded summits and polished rock faces. Its slopes support diverse plant communities, including one of Washington’s few known sites for the Okanogan fameflower. Fire has long influenced the mountain’s ecology, and because it lies near Republic and State Route 20, it remains a significant management concern.