Isaac Buchanan (July 21, 1810 – October 1, 1883) was a businessman and political figure in Canada West. He was also an international merchant, first president of the Hamilton Club, founder of Hamilton and Toronto boards of trade - forerunners to modern chambers of commerce - and founder of the regiment that later became the Royal Hamilton Light Infantry.
He was born in Glasgow, Scotland in 1810 and became an apprentice to a firm of Glasgow merchants in 1825. He became a junior partner in a new Montreal wholesale business opened by the firm; Buchanan moved to York (Toronto) to be closer to clients in Upper Canada. In 1834, with his brother Peter, he bought the business in York and set up an office in Glasgow. He served in the local militia during the Upper Canada Rebellion. In 1840, he set up a new company in Hamilton; a Montreal branch was also established. In 1841, he was elected to the Legislative Assembly for the city of Toronto; he resigned his seat in 1843. In 1844, the Toronto branch of his business was closed and the operation in Hamilton was expanded. He helped establish the Free Church of Scotland in Canada West. In 1844, he moved to Hamilton, where he helped set up the Board of Trade, becoming its first president. In 1848, upset by the repeal of the Corn Laws in Britain, he left the business and moved back to Scotland, where he campaigned against free trade in Britain. In 1851, he rejoined the business and returned to Hamilton. He was a director in the Great Western Railway and he attempted to promote its development over those of the competing Grand Trunk Railway. In 1857, he was elected to the Legislative Assembly for Hamilton. While in office, he attempted to promote his railway interests but also negotiated refinancing of the city of Hamilton's debts after it borrowed heavily to finance infrastructure improvements. Buchanan also served as lieutenant-colonel in the local militia. He supported protectionist trade policies and opposed representation by population. His political interests distracted him from his business interests and, although he resigned his seat in 1865, the business failed in 1867. He sold his estate in Hamilton. Buchanan received a government appointment in 1879 which sustained him through his later years. He died in Hamilton in 1883.
Isaac Buchanan married Agnes Jarvie, daughter of Robert Jarvie, on January 27, 1843. The couple had eleven children. The couple entertained at the family home, "Auchmar", Clairmont Park, Hamilton. In 1862, when Mr. Buchanan was appointed the first commanding officer of the 13th Militia Regiment, Mrs. Buchanan presented to it a stand of colours. Mr. Buchanan died at Hamilton, October, 1883, aged 73. Mrs. Buchanan died in Hamilton, May 7, 1896, aged 71. One of the couple`s sons, James Isaac Buchanan, Esquire, worked as a banker in Pittsburg, Pa.
The Buchanan neighbourhood on the Hamilton, Ontario mountain was named after him. It is bounded by Fennell Avenue West (north), Mohawk Road West (south), Garth Street (west), and West 5th Street (east). Landmarks in this neighbourhood include Mohawk College, Hillfield-Strathallan College, Mohawk Trail School Museum and Buchanan Park, which was also named after him.
His original estate, the Claremont Lodge and Auchmar Estate, a house and gate lodge in the Carpenter Gothic Cottage style of architecture were built for the Honourable Isaac Buchanan in 1855. The buildings still stand at the corner of Fennell Avenue West and West 5th Street and are currently a Hamilton Heritage site.
- Hemsworth, Wade (2007-04-28). "City looks at rezoning Auchmar". The Hamilton Spectator.
- Bailey, Thomas Melville (1981). Dictionary of Hamilton Biography (Vol I, 1791-1875). W.L. Griffin Ltd.
- Morgan, Henry James Types of Canadian women and of women who are or have been connected with Canada : (Toronto, 1903) 
- http://www.heritagefdn.on.ca/userfiles/HTML/nts_1_7196_1.html Ontario Heritage Trust Claremont Lodge and Auchmar 1855
- "Auchmar Estate". Heritage Watch Hamilton. 2007. Retrieved 2007-05-14.
- MapArt Golden Horseshoe Atlas - Page 657 - Grids K10, K11
- Biography at the Dictionary of Canadian Biography Online
- The American System in Canada
- An online tribute to Isaac Buchanan