Kostanay (Kazakh: Қостанай, translit. Qostanaı, قوستاناي) is a city located on the Tobol River in northern Kazakhstan. It was known as Nikolayevsk (Russian: Николаевск) until 1895 and then as Kustanay (Russian: Кустанай) until 1997. Kostanay is the administrative center of the Kostanay Region.