Sakha, officially the Republic of Sakha (Yakutia), is the largest republic of Russia, located in the Russian Far East, along the Arctic Ocean, with a population of roughly 1 million. Sakha comprises half of the area of its governing Far Eastern Federal District, and is the world's largest country subdivision, covering over 3,083,523 square kilometers (1,190,555 sq mi). Yakutsk, which is the world's coldest major city, is its capital and largest city. The republic has a reputation for an extreme and severe climate, with the lowest temperatures in the Northern Hemisphere being recorded in Verkhoyansk and Oymyakon, and regular winter averages commonly dipping below −35 °C (−31 °F) in Yakutsk. The hypercontinental tendencies also result in warm summers for much of the republic.

Sakha was first home to hunting-gathering and reindeer herding Tungusic and Paleosiberian peoples such as the Evenks and Yukaghir. Migrating from the area around Lake Baikal, the Turkic Sakha people first settled along the middle Lena river sometime between the 9th and 16th centuries, likely in several waves, bringing the pastoral economic system of Central Asia with them.

The Russians colonised and incorporated the area as Yakutsk Oblast into the Tsardom of Russia in the early-mid 17th century, obliging the indigenous peoples of the area to pay fur tribute. While the initial period following the Russian conquest saw the Sakha population drop by 70%, the Imperial period also saw the expansion of the native Yakuts from the middle Lena along the Vilyuy River to the north and the east displacing other indigenous groups. Yakutia saw some of the last battles of the Russian Civil War, and the Bolshevik authorities re-organized Yakutsk Oblast into the autonomous Yakut ASSR in 1922. The Soviet era saw the migration of many Slavs, specifically Russians and Ukrainians, into the area.

On September 27, 1990, the area became the Yakutskaya-Sakha Soviet Socialist Republic, and on December 27, 1991, it became the "Republic of Sakha (Yakutia)" (in Russian, "Республика Саха (Якутия)").