Linkou County (Chinese: 林口县; pinyin: Línkǒu Xiàn) is an administrative subdivision of the province of Heilongjiang, China. It is under the jurisdiction of the prefecture-level city of Mudanjiang.
The population of the district was 434,101 in 1999.
Coordinates: 45°21′N 130°08′E / 45.350°N 130.133°E