古芝县（Củ Chi），又名苟知县。位于胡志明市西北，西贡河边，平均海拔8到10米。上连西宁省，东接平阳省。面积434.5平方千米，人口355822人，平均每平方千米819人，其中京族占84.4%，汉族占11%。现辖1市镇20公社。今日，本县有很多任务业区。居民多从事工业，农业，种植水稻。名胜有古芝地道等。

Củ Chi is a suburban district of Ho Chi Minh City, Vietnam.

During the American War from 1967, it served as base for the 269th Aviation Battalion of the United States Army.

It is famous for its Củ Chi tunnels, which were constructed during the Vietnam War, and served as headquarters for the Viet Cong. Today, the district has many industrial zones.