Kronotsky Nature Reserve, natural area set aside for research in the natural sciences, on the eastern coast of the Kamchatka Peninsula, eastern Russia. The reserve, established in 1934, has current boundaries that date from 1967 and an area of 4,243 square miles (10,990 square km). It contains the only geyser basin in Russia. The coastal mountain ranges have numerous extinct and active volcanoes, basalt rock flows, and thermal lakes and springs. The mountain and coastal tundra are composed of thickets of grasses, Russian rock birch forest, and dwarf birch scrub. Wildlife includes marmot, pika, Arctic ground squirrel, Steller’s sea lion, ringed seal, brown bear, reindeer, sable, bighorn sheep, and geese, ducks, and swans.