Cao County or Caoxian (simplified Chinese: 曹县; traditional Chinese: 曹縣; pinyin: Cáo Xiàn) is a county in Heze City in southwestern Shandong Province, China.

Prior to the Boxer Rebellion, Cao was an area noted for its lawlessness.

When local garrisons were weakened during the First Sino-Japanese War, a militia known as the Dadaohui ("Great Sword Company") was set up.

[3] Cao County, under Heze City in Shandong Province, China, according to the latest statistics, had a population of 1,682,369.

Cao County is an extensive agricultural producer from wheat and cotton to an expanding industrial base of manufacturing and textiles.