Augustine Volcano, Stratovolcano in Cook Inlet, Alaska.

Augustine is a stratovolcano in Cook Inlet, Alaska, covering the entirety of small Augustine Island. The summit area contains multiple lava domes and flows, surrounded by volcanic material that extends to the island's coastline.

Augustine's oldest dated deposits are about 40,000 years old, and at least eleven large rock avalanches reached the coast in the past 1,800 to 2,000 years. Documented major eruptions occurred around 1650, in 1812, in October 1883, from March to August 1935, from October 1963 to August 1964, in October 1971, from January 1976 to May 1977, from March to August 1986, and from January to April 2006.

The Sugpiaq gave the mountain the name Utakineq, while the Dena'ina call it Chu Nula. Both of these indigenous names remain in use throughout the region today.

The Alaska Volcano Observatory monitors the island with seismic instruments to detect signs of activity. The island is uninhabited and difficult to reach, so visits usually occur by air or boat from a safe distance.

The island displays 11 different debris avalanche deposits that reached the sea within the last 2000 years. These deposits shaped the irregular coastline visible from the water today.