The Kamchatka River rises northwest of Avacha and flows north down the central valley, turning east near Klyuchi to enter the Pacific south of Kamchatsky Point at Ust-Kamchatsk.

The obvious circular area in the central valley is the Klyuchevskaya Sopka, an isolated volcanic group southeast of the curve of the Kamchatka River.

There is considerable variation, however, between the rain-drenched and heavily glaciated east coast and the drier and more continental interior valley.

In the heavily glaciated Kronotsky Peninsula, where maritime influences are most pronounced, annual precipitation can reach as high as 2,500 millimetres (98 in), whilst the southeast coast south of Petropavlovsk-Kamchatsky generally receives around 1,166 millimetres (45.9 in) of rainfall equivalent per year.

The interior valley of the Kamchatka River, represented by Klyuchi, has much lower precipitation (at around 450 to 650 millimetres (18 to 26 in)) and significantly more continental temperatures, reaching 19 °C (66 °F) on a typical summer day and during extreme cold winter spells falling as low as −41 °C (−42 °F).

Sporadic permafrost prevails over the lower part of this valley, but it becomes more widespread at higher altitudes and glaciers, and continuous permafrost prevails north of 55˚° N. The summer months, when maximum temperatures range from 15 to 20 °C (59 to 68 °F), are popular with tourists, but a growing trend in winter sports keeps tourism pulsing year-round.

The volcanoes and glaciers play a role in forming Kamchatka's climate, and hot springs have kept alive dozens of species decimated during the last ice age.

[7] The Kamchatka River and the surrounding central side valley are flanked by large volcanic belts containing around 160 volcanoes, 29 of them still active.

[9] Many have highly symmetrical cones, and Kronotsky is viewed by volcanologists Robert and Barbara Decker as a prime candidate for the world's most beautiful volcano.

[14] Prior to Russian discovery, the peninsula was inhabited by various Chukotko-Kamchatkan peoples (specifically the Itelmen, Koryak, and Alyutor).

There were numerous mutinies and native wars all over the peninsula and north to the Koryak country of the Penzhina River and Olyutor Gulf.

Vitus Bering's Second Kamchatka Expedition (ca 1733–1743), in the service of the Russian Navy, began the final "opening" of Kamchatka, helped by the fact that the government began to use the area to exile people, famously the Hungarian nobleman and explorer the Count de Benyovszky in 1770.

The Russian government encouraged the commercial activities of the Russian-American Company by granting land to newcomers on the peninsula.

Despite the successful defense, the Russians abandoned Petropavlovsk as a strategic liability after the French and British forces withdrew.

On 24 May 1861, the ship Polar Star (475 tons), of New Bedford, wrecked on the west coast of Kamchatka during a dense fog and gale.

The rest of the crew were saved by the barque Alice, of Cold Spring, and the ship Oliver Crocker, also from New Bedford.

The naval port moved to Ust-Amur, and in 1867, Russia sold Alaska to the United States, making Petropavlovsk obsolete as a transit point for traders and explorers on their way to the American territories.

[18] World War II (1939–1945) hardly affected Kamchatka except for its role as a launch site for the invasion of Manchuria in August 1945.

Vilyuchinsk, located on the Kamchatka Peninsula about 20 kilometers (12 mi) across Avacha Bay from Petropavlovsk-Kamchatsky, was founded as Sovetsky in 1968 through the amalgamation of three earlier settlements which supplied the Soviet Navy as a submarine constructor; it is the home base of the Russian Pacific fleet.

The variable climate promotes different flora zones where tundra and muskeg are dominant, succeeded by grasses, flowering shrubs, and forests of pine, birch, alder, and willow.

The wide variety of plant forms spread throughout the Peninsula promotes a similar diversity in animal species that feed off the flora.

This is due to many factors, including a wide range of climates; diverse topography and geography; many free-flowing rivers; proximity to the highly productive waters of the northwestern Pacific Ocean, the Bering, and the Okhotsk Seas; low human population density; and minimal development.

[23] Other fauna of note include carnivores such as tundra wolf (Canis lupus albus), Arctic fox (Vulpes lagopus), Anadyr fox (Vulpes vulpes beringiana), East Siberian lynx (Lynx lynx wrangeli), wolverine (Gulo gulo), sable (Martes zibellina), Eurasian otter (Lutra lutra), East Siberian stoat (Mustela ermine kaneii), and Siberian least weasel (Mustela nivalis pygmaea).

The peninsula hosts habitat for several large ungulates including the Kamchatka snow sheep, reindeer (Rangifer tarandus), and Chukotka moose (Alces alces buturlini), one of the largest moose in the world and the largest in Eurasia, and rodents/leporids, including mountain hare (Lepus timidus), marmot, and several species of lemming and squirrel.

Kamchatka most likely contains the world's greatest diversity of salmonid fish, including all six species of anadromous Pacific salmon (chinook, coho, chum, seema, pink, and sockeye).

Due to its uniquely suitable environment, biologists estimate that a fifth of all Pacific salmon originates in Kamchatka.

Seabirds include murrelets,[27] Northern Fulmars, Thick- and Thin-billed Murres, Kittiwakes, Tufted and Horned Puffins, Red-faced, Pelagic, and other Cormorants, and many other species.

Points of interest on the Kamchatka Peninsula include thermal and mineral springs, volcanoes, glaciers, a diversity of plants and animals, and other natural features largely untouched by civilization.

Activities include sport fishing, alpine tourism, heliskiing, snowboarding, dog sledding, and surfing.