Dayu (Chinese: 大余; pinyin: Dàyú) is a county in the west of the prefecture-level city of Ganzhou, in the southwest of Jiangxi Province, bordering Guangdong Province to the south.

Dayu has an area of 1,367.63 km2 (528.04 sq mi).

The county executive, legislature, judiciary are at Nan'an Town (Nanan) (南安镇), together with the CPC and PSB branches.

Dayu county is divided to 8 towns and 3 townships.

This Jiangxi location article is a stub.