Unified Silla Dynasty
- 16th year of reign of King Gyeongdeok (757) : Muan-gun of Muju
Goryeo Dynasty
- First year of reign of King Hyejong (944) : Mullyang-gun
- 10th year of reign of King Seongjong (991) : Muan-gun of Najumok
- Second year of reign of King Myeongjong (1172) : Muan-hyeon
Joseon Dynasty
- 13th year of reign of King Taejong (1413) : Muan-hyeon of Jeolla-do (governor)
- 32nd year of reign of King Gojong (1895) : Muan-gun of Najubu
- First year of King Gojong's proclamation of Geonyang (1896) : Muan-gun of Jeolla-do
- First year of King Gojong's proclamation of Gwangmu (1897) : Promoted to Muan-bu
Japanese Colonial Era
- March 1, 1914 : Muan-gun (Separated Mokpo-bu)
- April 4, 1939 : Seokgok-myeon changed into Mongtan-myeon
Republic of Korea
- November 6, 1957 : Changed Myeonseong-myeon into Muan-myeon
- January 1, 1969 : Sinan-gun separated from Muan-gun
- May 1, 1979 : Promotion of Muan-eup
- December 1, 1980 : Promotion of Illo-eup
- February 15, 1983 : Promotion of Unnam-myeon, 2 eup's and 7 myeon's, 103 legislative ri's, 399 administrative ri's
- January 3, 2011 : 3 eup's, 6 myeon's, 103 legislative ri's, 399 administrative ri's
- August 8, 2011 : 3 eup's, 6 myeon's, 103 legislative ri's, 416 administrative ri's
- March 4, 2019 : 3 eup's, 6 myeon's, 103 legislative ri's, 417 administrative ri's