First Newspaper 1793
The Upper Canada Gazette or American Oracle, first newspaper in what is now Ontario, was published in the town of Niagara. Its first issue, edited by Louis Roy, appeared April 18, 1793. On this site was published the Gleaner which from 1817 to 1837, under the editorship of Andrew and Samuel Heron, was one of the most prominent newspapers in Upper Canada.
Plaque via Alan L. Brown's site Ontario Plaques. Full page here.