呉県
Gu Yong was born in Wu County, Wu Commandery, which is present-day Suzhou, Jiangsu, towards the end of the Eastern Han dynasty. His great-grandfather Gu Feng () was a former Administrator () of Yingchuan Commandery (潁川郡; around present-day Xuchang, Henan). The Gu clan, which he was from, was one of the four most influential clans in Wu Commandery and also in the Jiangdong region at the time.