Charter franchises were in the Illinois cities of Belleville, Centralia, Marion, Mattoon, Mount Vernon and West Frankfort.
The league incorporated the new Paducah Chiefs and the five former Illinois State League teams, the Belleville Stags, Centralia Cubs, Mattoon Indians, Mount Vernon Kings, and West Frankfort Cardinals as 1949 charter members.
The Mississippi–Ohio Valley League added expansion teams in the Paris Lakers and Vincennes Velvets.
[5] There was more movement in 1951, as the Springfield Giants and West Frankfort Cardinals both folded and the Paducah Chiefs left to join the Kentucky–Illinois–Tennessee League.
[6][3] In 1952, the league again expanded to eight teams, adding the Commodores in Decatur, Illinois and Cardinals in Hannibal, Missouri, while Vincennes relocated to Canton, Ohio.
[8][3] There was expansion again in 1954, as two Iowa teams, the Clinton Pirates and Dubuque Packers returned the league to eight members.
[3][9] In the final season of the league, the Danville Dans moved to Kokomo, Indiana and became the Kokomo Giants and Mount Vernon moved to Lafayette, Indiana as the Lafayette Red Sox.
Following the 1955 season, Hannibal moved to become the Michigan City White Caps, joining Kokomo, Lafayette, Clinton, Dubuque, Decatur, Mattoon and Paris in the renamed Midwest League.