The 1888 season opened with teams in eight cities - Chicago, Des Moines, Kansas City, Milwaukee, Minnesota, Omaha, St. Louis and St. Paul. Four of these clubs (Des Moines, Milwaukee, Minneapolis and St. Paul) were in the Northwestern League in 1887. Kansas City and Omaha came from the Western League in 1887. Chicago and St. Louis were stating new clubs, but were backed by the owners of existing major league clubs in those two cities.
| City | Sponsor |
| Chicago | Sam G. Morton |
| Des Moines | C.M. Sherman |
| Kansas City | E.E. Menges |
| Milwaukee | James A. Hart |
| Minneapolis | R.O. Foser |
| Omaha | E.G. Briggs |
| St. Louis | Tom J. Loftus |
| St. Paul | A.M. Thompson |
Rosters and signings as published in various papers between October 30, 1887 and the end of 1887, including theChicago Tribune (October 30, 1887 and November 3, 1887), the Oshkosh Northwestern (November 1, 1887), the St. Paul Globe (November 6, 1887), the Nebraska State Journal (November 20, 1887), and the Chicago Inter Ocean (January 8, 1888). The lists varied a bit over time, but this represents the state of the clubs heading into 1888.
| Chicago Fred Lange Dan E. Dugdale E. F. (Moxie) Hengle John Crogan John E. Dunn George Rooks Herman C. Long L. N. (Jumbo) Schoenck J. E. Dallas Gene Moriarty J.M. Nicholson Charlie Sprague J. A. McCauley |
Des Moines Harry Sage Joe Quinn Dan Stearns Bill J. Van Dyke Billy C. Alvord Bill Traffley F. C. Smith J. F. Macullar William M. Traffley G. Whiteley Frank Wells |
| Kansas City J. R. Johnson J. H. Manning J. B. Gunson P. B. Swartzell C. L. Reynolds James Conway Jake Wells Ed Cartwright Joseph A. Ardner John A. McCarty William Hassamer C. C. Campau M. Bradley |
Miwaukee E. Lynn Mills Bill Shenkel Will Fuller Alex Ferson Pat E. Pette Joe Strauss Bobby L. Lowe David J. Davin |
| Minnesota Mike Lynch W.F. Jordan George Klopf Bill Hawes Thomas McCullom George E. Winkleman Tim Brosnan J. W. Shaw O. J. Patton |
Omaha George Wilson James J. Cooney Thomas Lovett Edward Cassian James Walsh Daniel Shannon John Doran John Campana William Annis John Messitt Pat H. O'Connell William B. Burdick Joe Miller James M. Burns |
| St. Louis Ed Knauff Charles Alcott Thomas Dolan H. F. Hines Nicholson James Devlin Harry Staley Jake Kenyon Harry P. Lyons Joe Herr Thomas McCarthy James McCormick Ed Sproat B. L. Cantz Jake Beckley Charles Crooks F. B. Weikert |
St. Paul William Sowders William Earle R. Kemmler Thomas J. Morrissey John Pickett Tayolr Shafer John Corbett Charkes Reilly John Sowders Joe L. Quest Joseph Duryea Fred Jevne P.L. Murphy J. E. Bingham V. C. Anderson |
