Illinois-Iowa League was an independent league.
1890 Aurora IL, Cedar Rapids IA, Dubuque IA, Joliet IL, Monmouth IL, Ottawa IL, Ottumwa IA, Sterling IL. During the season, Sterling moved to Galesburg IL, then to Burlington IA.
1891 Davenport IA, Quincy IL, Rockford IL entered the league and Burlington, Dubuque and Monmouth left the league.
1892 Evansville In, Jcksonville IL, Joliet IL, Rock Island-Moline IL, Rockford IL, Terre Haute In