The Kamchatka Peninsula (Russian: полуо́стров Камча́тка, poluostrov Kamchatka) is a 1,250-kilometre (780 mi) peninsula in the Russian Far East, with an area of about 270,000 km2 (100,000 sq mi). It lies between the Pacific Ocean to the east and the Sea of Okhotsk to the west. Immediately offshore along the Pacific coast of the peninsula runs the 10,500-metre (34,400 ft) deep Kuril-Kamchatka Trench.
The Kamchatka Peninsula, the Commander Islands, and Karaginsky Island constitute the Kamchatka Krai of the Russian Federation. The vast majority of the 322,079 inhabitants are Russians, but there are also about 8,743 Koryaks (2002). More than half of the population lives in Petropavlovsk-Kamchatsky (179,526 people in 2010) and nearby Yelizovo (38,980).
The volcanoes of Kamchatka are a large group of volcanoes situated on the Kamchatka peninsula. The Kamchatka River and the surrounding central side valley are flanked by large volcanic belts containing around 160 volcanoes, 29 of them still active. The peninsula has a high density of volcanoes and associated volcanic phenomena, with 19 active volcanoes being included in the six UNESCOWorld Heritage List sites in the Volcanoes of Kamchatka group, most of them on the Kamchatka Peninsula.
The highest volcano is Klyuchevskaya Sopka (4,750 m or 15,584 ft), the largest active volcano in the Northern Hemisphere, while the most striking is Kronotsky, whose perfect cone was said by celebrated volcanologists Robert and Barbara Decker to be a prime candidate for the world's most beautiful volcano. Somewhat more accessible are the three volcanoes visible from Petropavlovsk-Kamchatsky: Koryaksky, Avachinsky, and Kozelsky. In the center of Kamchatka is Eurasia's world famous Geyser Valley which was partly destroyed by a massive mudslide in June 2007.
Owing to the Kuril-Kamchatka Trench, deep-focus seismic events and tsunamis are fairly common. A pair of megathrust earthquakesoccurred off the coast on October 16, 1737, and on November 4, 1952, in the magnitude of ~9.3 and 8.2 respectively. A chain of more shallow earthquakes were recorded as recently as April 2006.