Qin'an County (Chinese: 秦安县; pinyin: Qín'ān Xiàn) is a county in the east of Gansu province, China.

[2] The area has been inhabited since prehistoric times, as evidenced by 68 Neolithic cultural sites including the Dadiwan culture.

[2] It is reputedly the county where Zhuge Liang's troops, commanded by Ma Su, were defeated by Zhang He at the Battle of Jieting.

Known historically as Chengji (成紀), it vied with Tianshui (then known as Shanggui) as the seat of the medieval province of Qinzhou during the Tang dynasty and Five Dynasties eras.

It is celebrated yearly on the 15th of the third lunar calendar months.