Nun Mountain

[4] Precipitation runoff and glacial meltwater from the mountain's slopes drains to Lynn Canal.

Although modest in elevation, topographic relief is significant as the summit rises over 4,300 feet (1,311 meters) above tidewater of Lynn Canal in four miles (6.4 km) and the northeast face rises 3,300 feet (1,006 meters) in one mile (1.6 km).

The mountain's name was published by the United States Coast and Geodetic Survey in 1924 and the toponym has been officially adopted by the United States Board on Geographic Names.

[5] Weather systems coming off the Gulf of Alaska are forced upwards by the mountains (orographic lift), causing heavy precipitation in the form of rainfall and snowfall.

This climate supports a small unnamed glacier in the peak's northwest cirque.