Edmund Bailey O'Callaghan, (probably 27 February 1797 – 29 May 1880) was an Irish doctor, historian and journalist.

[1] Born in Mallow, County Cork, Ireland, he studied medicine in Paris and immigrated to Lower Canada in 1823 where he became involved in the political reform movement of the Parti patriote.

[citation needed] On the death of Daniel Tracey, owner of the Montreal Vindicator newspaper, in 1832 O'Callaghan became the editor and brought in Thomas Storrow Brown to work on the paper.

They proved to be an irreducible adversary of Lord Gosford and the status quo.

[2] In 1837, during the Lower Canada Rebellion, a mandate of arrest was issued against him, and he sought refuge at Saint-Denis, then crossed the United States border with his friend, Louis-Joseph Papineau.