Porphyry Mountain is a prominent 6,375-foot (1,943 meter) mountain summit located in the Wrangell Mountains, in the U.S. state of Alaska. The peak is situated in Wrangell-St. Elias National Park and Preserve, immediately southeast of Kennecott, northeast of McCarthy, and, northwest of Sourdough Peak. Precipitation runoff from the mountain drains into tributaries of the Nizina River, which in turn is part of the Copper River drainage basin. The peak is notable for a rock glacier on its north slope. The mountain was so named because it is largely composed of porphyry, which is a very hard igneous rock. The mountain's local name was reported in 1908 by the U.S. Geological Survey. On a clear day the summit of Porphyry Mountain offers views of Donoho Peak, Kennicott Glacier, and Mount Blackburn to the northwest, and Fireweed Mountain to the west.