The Sungacha or Songacha (Russian: Сунгача Sungacha or Сунгач Sungach, Chinese: 松阿察河; pinyin: Sōngàchá Hé) is a river marking part of the border between the Russian Federation and the People's Republic of China. It is a left tributary of the Ussuri, and the only outflow of Khanka Lake.

The 180-to-210-kilometer (110 to 130 mi)-long Sungacha's length fluctuates, as the stream bed changes every year. The area of its basin is approximately 25,600 km (9,900 sq mi), of which 21,000 km (8,100 sq mi) within Russia.

The river supports a rich diversity of flora and fauna, including Nelumbo nucifera in its basin.

The Sungacha's waters come from rain, snow and springs.