1845 to 1868 in baseball

At its December 1868 annual meeting, the National Association of Base Ball Players (NABBP) permitted professional clubs.

This table covers all of those "majors" (not marked), all of the 1869 "pros" (*), all 14 member clubs with at least twelve wins on record, and a few others.

At least four Association clubs not listed here would someday try professionalism: Riverside of Portsmouth, Ohio (1870); Kekionga of Fort Wayne, Indiana (1871); Middletown of Mansfield, Connecticut (1872); Resolute of Elizabeth, New Jersey (1873).

For the fifteen listed clubs in Greater New York, no city is named in the first column; the comment gives their locales.

Bill Ryczek calls 19 teams "major" in the first season that he covers: sixteen of the members and three others (Lowell, Harvard, and Camden).