Tonghe County (simplified Chinese: 通河县; traditional Chinese: 通河縣; pinyin: Tōnghé Xiàn; lit. 'Pass river') is under the administration of Harbin, the capital of Heilongjiang province, People's Republic of China, located on the northern (left) bank of the Songhua River. It is 161 kilometres (100 mi) to the east of central Harbin, bordering Yilan County to the east, Fangzheng County to the south, Mulan County to the west, as well as the prefecture-level city of Yichun to the north.

Tonghe County has a monsoon-influenced humid continental climate (Köppen Dwa/Dwb), with long, very dry, bitterly cold winters, very warm and humid summers, and short, rather dry spring and autumn in between. Its location in the Songhua River Valley at an elevation of 107 m (351 ft) allows for cool air to pool in and around the county seat, depressing temperatures slightly as compared to Harbin. The monthly 24-hour average temperature ranges from −20.4 °C (−4.7 °F) in January to 22.1 °C (71.8 °F) in July, and the annual mean is +2.93 °C (37.3 °F). Close to 65% of the annual precipitation occurs from June to August. With monthly percent possible sunshine ranging from 46% in July to 66% in February, the area receives 2,413 hours of bright sunshine annually, with the latter half of winter being especially sunny.

There are eight towns in the county:^[7][8]

The population of the district was 234,662 in 1999.^[9]

• China National Highway 221
• G1011 Harbin–Tongjiang Expressway