Mississippi-Ohio Valley League was a Class D League. Most of the teams from the Illinois State League formed this league. In 1956, the league changed its name to the current Midwest League
1949 Belleville IL, Centralia IL, Mattoon IL, Mt Vernon Il, Paducah KY, West Frankfort IL.
1950 Vincennes IN, Paris IL,and Springfield IL entered the league; Belleville left the league.
1951 Danville, IL entered the league; Paducah, Springfield and West Frankfort left the league.
1952 Decatur, IL and Hannibal, MO entered the league. The Vincennes franchise moved to Canton, IL during the season.
1953 Centralia and Canton left the league.
1954 Clinton, IA and Dubuque, IA entered the league.
1955 Kokomo, IN and Lafayette, IN entered the league; Danville and Mt Vernon left the league.