Siyang County (simplified Chinese: 泗阳县; traditional Chinese: 泗陽縣; pinyin: Sìyáng Xiàn) is under the administration of Suqian, Jiangsu province, China.

It borders the prefecture-level city of Huai'an to the southeast.

It is the earliest[citation needed] Chinese county and the Italian poplar tree were the highest poplar coverage of China as China polar tree industry county of the most developed county forestry of China and to learn the unique honor of "China YiYang township of" title of county the name.

In addition, SiYang because has the Chinese unique poplar museum, and hold China unique YangShuJie which is famous and well-known.

At present, Siyang County has 11 towns and 5 townships.