William Joseph Hanlon
- Bats Right, Throws Unknown
- Height 6' 0", Weight 175 lb.
- School Santa Clara University, Saint Mary's College of California
- Debut April 16, 1903
- Final Game April 26, 1903
- Born June 24, 1876 in Los Angeles, CA USA
- Died November 23, 1905 in Los Angeles, CA USA
Big Bill Hanlon was the first major leaguer born in Los Angeles, CA, at a time when L.A. was still a small town that had a reputation as the toughest town in the country. Hanlon came to the majors to play eight games at first base for the Chicago Cubs in 1903, on a team whose regular first baseman was Frank Chance. Chance was a year younger than Hanlon.
Hanlon also played in the minors for teams in California and on the West Coast.