Lake Khasan or Lake Hassan (Russian: озеро Хасан; Chinese: 哈桑湖; pinyin: Hāsāng Hú) is a small lake in Khasansky District, Primorsky Krai of Russia, located southeast of Posyet Bay, on the border with North Korea and China, 130 km southwest of Vladivostok. It has a surface area of 2.23 km². The Tanbogatyi River flows from the lake.