Sakhalin Oblast is a federal subject of Russia comprising the island of Sakhalin and the Kuril Islands in the Russian Far East. The oblast has an area of 87,100 square kilometers (33,600 sq mi). Its administrative center and largest city is Yuzhno-Sakhalinsk. As of the 2021 Census, the oblast has a population of roughly 500,000.

Sakhalin is an island in Northeast Asia. Its north coast lies 6.5 km (4.0 mi) off the southeastern coast of Khabarovsk Krai in Russia, while its southern tip lies 40 kilometres (25 mi) north of Japan's Hokkaido. A marginal island of the West Pacific, Sakhalin divides the Sea of Okhotsk to its east from the Sea of Japan to its southwest. It is administered as part of Sakhalin Oblast and is the largest island of Russia, with an area of 72,492 square kilometres (27,989 sq mi). The island has a population of roughly 500,000, the majority of whom are Russians. The indigenous peoples of the island are the Ainu, Oroks, and Nivkhs, who are now present in very small numbers.