|Surface area||77 km2 (30 sq mi)|
|Average depth||176 m (577 ft)|
|Max. depth||306 m (1,004 ft)|
|Surface elevation||103 m (338 ft)|
|Elevation||81 m (266 ft)|
|Last eruption||6440 BCE ± 25 years|
Kurile Lake (Russian: Кури́льское о́зеро "Kuril’skoye Ozero", aka "Keuay") is a large caldera containing a crater lake located at the southern tip of Kamchatka Peninsula, within the Southern Kamchatka Wildlife Refuge in Russia.
It has an area of 77 square kilometres (30 sq mi) (the third largest by area of all lakes in Kamchatka and the second among the freshwater lakes, second only to Kronotsky lake). The lake has an average depth of 176 metres (577 ft), and a maximum depth of 306 m (1,004 ft). The lake is fed by snowmelt, rain and a few rivers and streams: the Etimynk, Hakytsin, Vychenkiya and Kirushutk. From the lake flows the Ozernaya (Lake) river into the Sea of Okhotsk to the west. The magnitude of fluctuation in the water level is one to three meters (the highest levels are from May to June and the lowest in April). The average water temperature off the shore is between six and seven degrees Celsius in September.
In the north-east coast is the dormant volcano Ilinskaya (Elijah). There are a few islands in the lake, the largest of which, Samang, is 0.66 km². Other islands include Chayachy, Serdtse (Heart), Nizkii (Low), and Glinyanii (Clay). There are hot mineral springs in the area.
The Kurile lake caldera was formed by two large volcanic explosions, one 41,500 radiocarbon years ago and the other around 6440 BC.
The huge amount of material ejected during the second explosion, comparable to some of the largest eruptions in recorded history, produced thick pyroclastic flow deposits around the countryside, and some ash fell more than 1000 km away on the Asian mainland.
The pyroclastic-flow deposit is about 100-m thick at a location on the Ozernaya River, 3 km west of Kurile Lake, forming a spectacular curtain of cliffs, known as Kuthiny Baty ("vertical standing boat") because of its erosionally fluted formation.
The explosion of around 6440 BC is given a score of 7, the second highest ranking on the Smithsonian Global Volcanism Program's Volcanic Explosivity Index, making it comparable to some of the largest eruptions in recorded history such as Santorini, Changbaishan, Crater Lake, Kikai and Tambora.
The lake is the largest spawning ground for sockeye salmon in Eurasia, and second in the world only to Alaska. Measurements of the numbers of salmon entering the lake and the spawning of juvenile fish are conducted by observation stations (manned by the Pacific Research Institute of Fisheries and Oceanography (Тихоокеанский научно-исследовательский рыбохозяйственный центр or ТИНРО)) which is located on the western shore of the lake.
On the shores of the lake up to 100 brown bears are often sighted catching salmon.
Kurile Lake is a national wildlife preserve and a national monument. It is a UNESCO World Heritage Site in the listings of composition of the volcanoes of Kamchatka.
Tourist access is by small plane from Petropavlovsk to Ozernovsky, by truck to Pauzetka, then by 6-wheel drive army truck and on foot 
- Zaretskaia, N. E. et al. (2001). "Radiocarbon dating of the Kurile Lake caldera eruption (South Kamchatka, Russia)" (PDF). Geochronometria 20: 95–102.
- Ponomareva, V. V. et al. (2004). "The 7600 (14C) year BP Kurile Lake caldera-forming eruption, Kamchatka, Russia: stratigraphy and field relationships". Journal of Volcanology and Geothermal Research 136 (3–4): 199–222. Bibcode:2004JVGR..136..199P. doi:10.1016/j.jvolgeores.2004.05.013.
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- "Keuay: Russia". Geographical Names. Retrieved 2011-03-29.
- "Global Volcanism Program | Ilyinsky". volcano.si.edu. Retrieved 2014-02-22.
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- "Discovering Kamchatka: Terrestrial and aquatic fauna". The Royal Geographical Society. 2008. Retrieved 2012-08-14.
- Diana Gealdhill, "Kamchatka", Odyssey Books,2007