Daniel Ryan Sr. (1861/1862–1923) was an Irish-American politician who served as a member and president of the Cook County Board of Commissioners.

[3] In 1912, there was a split in the local Democratic Party, with those allied with Roger C. Sullivan and Edward Fitzsimmons Dunne being divided against those who were allied with Carter Harrison IV and William Randolph Hearst.

[4] Ryan served on the Cook County Board of Commissioners for nine years.

[7] Ryan was a leading figure in the early development of the Forest Preserve District of Cook County.

[2] Anton J. Cermak was chosen for the 1922 Democratic nomination for county board president over Ryan when the Democratic Party of Cook County organization selected their slate, a move that Parke Brown of the Chicago Tribune attributed to Ryan's "alliance with Thompsonism".