During the Samhan , Miryang may have been part of the territory of Mirimidongguk, one of the Byeonhan tribes mentioned in the "San guo zhi". Thereafter, it is believed to have been ruled by Geumgwan Gaya before being annexed by Silla. The "Samguk Sagi" records Mirimidongguk as being annexed by Jijeung of Silla in 505. In this period it was known as Chuhwa-gun (). Under the general reformation of names carried out by King Gyeongdeok in the 8th century, the name was changed to "Milseong-gun" ().