Siberia

The word "Siberia" originates from the Tatar word sibir, which means "sleeping land." This 5,207,900 square mile region has always been characterized as a bleak and desolate locale, despite its abundance of natural resources, including gas, oil, timber, and minerals. The region of Siberia consists of the vast Asian portion of Russia, as well as northern Kazakhstan. It is comprised of three distinct geographic areas: the swamplands of the West Siberian Plain, the heights of the Central Siberian Plateau, and the jagged system of mountains that stretches from the Lena River to the Pacific coast. Just southeast of the Central Siberian Plateau lies Lake Baikal, the world's deepest lake and home to one-fifth of the earth's fresh surface water and a diversity of plant and animal species. In addition to its brutal landscape, the region is blocked from the west by the Ural Mountains, from the north by the Arctic Ocean, from the east by the Pacific Ocean and the Bering Strait, and from the south by China, Mongolia, and Kazakhstan.

From the game's History encyclopedia, AoE3: DE 100.19.18309.