The Sevastopol Naval Base is an occupied naval base located in Sevastopol, in the disputed Crimean Peninsula. The base is used by the Russian Navy, and it is the main base of the Black Sea Fleet. Internationally it's recognised as Ukrainian land under Russian occupation.

Sevastopol, sometimes written Sebastopol, is the largest city in Crimea and a major port on the Black Sea. Due to its strategic location and the navigability of the city's harbours, Sevastopol has been an important port and naval base throughout its history. Since the city's founding in 1783 it has been a major base for Russia's Black Sea Fleet. During the Cold War of the 20th century, it was a closed city. The total administrative area is 864 square kilometres (334 sq mi) and includes a significant amount of rural land. The urban population, largely concentrated around Sevastopol Bay, is 479,394, and the total population is 547,820.