The Lena River is a major river in Siberia, Russia. It is the 11th longest river in the world and the 4th longest in Russia. It is also the largest river that flows entirely within Russia. The Lena River originates in the Baikal Mountains and flows northward for 4, 400 kilometers before emptying into the Laptev Sea. Along its course, it passes through several cities, including Yakutsk, the capital of the Sakha Republic. The Lena River is an important source of transportation, energy, and food for the people of Siberia.