Mount Griggs, formerly known as Knife Peak Volcano, is a stratovolcano, which lies 10 km behind the volcanic arc defined by other Katmai group volcanoes. Although no historic eruptions have been reported from Mount Griggs, vigorously active fumaroles persist in a summit crater and along the upper southwest flank. The fumaroles on the southwest flank are the hottest, and some of the flank fumaroles can roar so loudly that they can be heard from the valley floor.^[1] The slopes of Mount Griggs are heavily mantled by fallout from the 1912 eruption of Novarupta volcano.^[3] The summit consists of three concentric craters, the lowest and largest of which contains a recent summit cone topped by two craters. The volume of the volcanic edifice is estimated at about 25 cubic kilometers (6.0 cu mi). Isotopic analysis indicates that the source of Griggs' magma is distinct from the other Katmai volcanoes.^[4]

Mount Griggs
NW view from west rim of Katmai caldera, July 1990
Highest point
Elevation	7,602 ft (2,317 m)[1]
Prominence	7,300 ft (2,200 m)
Listing	North America prominent 60th North America isolated 91st
Coordinates	58°21′26″N 155°06′13″W / 58.3572°N 155.1037°W / 58.3572; -155.1037[2]
Geography
Mount Griggs Alaska
Location	Katmai National Park and Preserve, Lake and Peninsula Borough, Alaska, U.S.
Parent range	Aleutian Range
Topo map	USGS Mount Katmai B-4
Geology
Mountain type	Stratovolcano
Volcanic arc/belt	Aleutian Arc
Last eruption	1790 BCE ± 40 years

The mountain was named for Dr. Robert Fiske Griggs (1881–1962), botanist, whose explorations of the area, after the eruption of Mount Katmai in 1912, led to the creation of Katmai National Monument by President Woodrow Wilson in 1918.^[5]