Lauchlan Mackinnon (26 February 1817 – 21 March 1888) was a pastoralist, politician and newspaper proprietor in colonial Australia. Mackinnon one of the most enterprising of the pioneer colonists of Victoria (Australia) and one of the proprietors of the Melbourne Argus from 1852 until his death.
Mackinnon was born in Kilbride, Isle of Skye, Scotland, the second son of John Mackinnon, a Presbyterian minister of Strath, Skye, and his wife Ann, daughter of Lauchlan Mackinnon of Corriechatachan, Skye. After being educated partly at home and subsequently at Broadford, Mackinnon entered the office of his uncle Mr. Lauchlan Mackinnon, a Writer to the Signet in Glasgow; but preferring a more active life, he in 1838 proceeded to Sydney.
In Australia Mackinnon at once engaged in the hazardous business of "overlanding", and succeeded in his dangerous mission of conveying stock from Sydney to Adelaide—a feat which attracted much attention at the time, as it was the first overland journey made between these distant points. A little later (in 1840) he made one of the earliest overland journeys with sheep from Sydney to Melbourne. The pastoral capabilities of the country attracted his attention, and he determined to settle in Australia Felix. He took up a run in the western district on the Loddon River, and subsequently removed to Mount Fyans. He was for some years associated in business with the late James Montgomery, and in 1852 he joined Edward Wilson, and became one of the proprietors of the Argus. Prior to this he had taken a prominent part in political life, particularly interesting himself in the agitation for the separation of Port Phillip District from New South Wales. He was one of the representatives for the Electoral district of Port Phillip in the Parliament of New South Wales in 1848, and vigorously supported its claims for justice from the governing authorities of New South Wales. He was a strong and earnest supporter of the anti-convict movement, and took a prominent part in the demonstration which was held in Melbourne in 1849, when the inhabitants resolved to oppose the landing of convicts from the ship Randolph by physical force, and to undergo any extremity of suffering rather than permit the colony to become a receptacle of felons.