The land now known as Damyang was originally called Chujahye-gun under the kingdom of Baekje. After Silla unified the Three Kingdoms, King Gyeongdeok standardized place names across the country into Sino-Korean form, renaming this area Chuseong-gun. Having already changed names twice across two dynasties, this land first received its present name, "Damyang," under the Goryeo dynasty. In 995 (the 14th year of King Seongjong's reign), the royal court established an administrative and military office here called the Damju Regional Military Command.
Twenty-three years later, in 1018 (the ninth year of King Hyeonjong's reign), the court reorganized the region into Damyang-gun and incorporated it under the jurisdiction of Naju. From Baekje's Chujahye-gun, through Silla's Chuseong-gun, to Goryeo's Damyang-gun at last, this land carried three different names across three dynasties. Over the nearly thousand years since, administrative boundaries and jurisdictions have shifted repeatedly, but the name "Damyang" itself has survived and continues in use today.