Captain Sir Charles MacMahon was an Australian politician who twice served as Speaker of the Victorian Legislative Assembly and as Chief Commissioner of Victoria Police. MacMahon was born County Tyrone, Ireland, to a wealthy Irish family and served in the British army. He obtained a veterinary diploma in 1852, and soon left for Australia to join the gold rush. He arrived in Melbourne on 18 November 1852.

Sir William MacMahon, 1st Baronet (1776–1837) was an Irish barrister and judge of the early nineteenth century. He was a member of a Limerick family which became politically prominent through their influence with the Prince Regent, later King George IV. He was the first of the McMahon Baronets of Dublin.