Below is a list of summer collegiate baseball leagues across the nation. The first list of summer collegiate leagues require teams to only have players that have college eligibility left.
Alaska Baseball League
Arizona Collegiate Wood Bat League
Atlantic Baseball Confederation
Atlantic Collegiate Baseball League
Boise Summer League
Cal Ripken Sr. Collegiate Baseball League
California Collegiate League
Cape Cod Baseball League
Clark C. Griffith Collegiate Baseball League
Cotton State Baseball League
Coastal Plain League
Florida Collegiate Summer League
Futures Collegiate Baseball League
Great Lakes Summer Collegiate
Great South League
Hamptons Collegiate Baseball
Hawaii Collegiate Baseball League
Horizon Air Summer Series
Jayhawk Baseball League
KIT League Baseball
M.I.N.K. Baseball League
Mountain Collegiate Baseball League
New England Collegiate Baseball League
New York Collegiate Baseball League
Northwoods League
Ohio Valley League
Pacific West Baseball League
Perfect Game Collegiate League
Prospect League
Southern Collegiate Baseball League
Sun Belt League
Texas Collegiate League
Valley Baseball League
Walter Johnson League
West Coast League
Western Baseball Association
Here are some of the other summer collegiate leagues in Illinois that do not have college eligibility requirements:
Metro Collegiate Summer Baseball League of Illinois
Midwest Collegiate League
Chicago Suburban Baseball League
Eastern Illinois Baseball League