The Guelph Mercury is an English language newspaper published in Guelph, Ontario, Canada. It publishes a mix of community, national and international news and is owned by the Torstar Corporation.

The newspaper, originally named the Guelph Advertiser, began publishing as a weekly in 1854 under the leadership of founder George Keeling. In 1862, Toronto newspaperman James Innes took over editorship of the Advertiser and shortly thereafter formed a partnership with John C. McLagan, owner of the competing weekly newspaper the Guelph Mercury. The two papers merged to form the Mercury and Advertiser.

The Mercury became a daily newspaper in 1867.

The Mercury has since had numerous owners. Innes sold his share in the newspaper in 1905 to J. Innes McIntosh, who also bought the Guelph Herald, a competing daily newspaper, in 1924. McIntosh then sold his share in 1929 to James Playfair, who sold the paper in the late 1940s to Thomson Newspapers Corporation. Thomson remained owner for half a century, until Hollinger Inc purchased the paper in 1995. Sun Media purchased then sold the paper in 1999. Torstar Corporation is the paper's current owner.

The Mercury is part of a group called Grand River Valley Newspapers, which includes The Record and The Cambridge Reporter.

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