William Macomb (ca 1751 – April 16, 1796) was a merchant and political figure of Upper Canada.
He was born in northern Ireland around 1751 and came to North America with his family in 1755. With his brother, Alexander, he became a major landowner and merchant in New York and Michigan; the brothers were the first owners of Grosse Ile, Michigan when it was deeded on July 6, 1776 from the Potawatomi Indians. William married Sarah Dring; she survived him, as did several children, including John W., Anne, Catherine, William, Sarah, Jane, David B., and Eliza. All of these children except John W. Macomb were minors at the time of the fire which destroyed Detroit in June 1805, according to land board records.[1]
In 1792, Macomb was elected to the 1st Parliament of Upper Canada, representing Kent with François Baby. He also served as a judge of the Court of Common Pleas for the District of Hesse; the district covered not only present-day Western Ontario, but extended to the settlements at Detroit and Michilimackinac, which were under British control at the time.
William Macomb's loyalties do not appear to have been tested, as he died at Detroit two months before the British evacuation in July 1796. Although it is impossible to say for certain what his ultimate stance might have been, his connections ran at the highest levels of both Canada and the fledgling United States. His brother Alexander had moved to New York City after the Revolution, where he quickly became a prominent land speculator. Alexander's house in New York briefly served as the second Executive Mansion for George Washington, before the Federal government moved to Philadelphia in 1790. Alexander's son and namesake would enter the United States Army upon the recommendation of no less than Alexander Hamilton and later fight in the War of 1812; he would be decorated for his command of American troops at the Battle of Plattsburgh in 1814, and in later years would be appointed Commanding General of the U.S. Army. The younger Alexander would marry his cousin Catherine in 1803; their descendants would serve the United States in both military and naval roles.
Although William Macomb is said to have relayed military intelligence to Colonel John Butler, a leader of Loyalist rangers and Canadian militia, John Graves Simcoe, the Lieutenant Governor of Upper Canada between 1791 and 1796, apparently distrusted Macomb's motives. Nevertheless, no demonstrable proof has been found to show that William was anything but a loyal servant of the Crown.
With 26 slaves at the time of his death, Macomb was apparently the foremost slaveholder in what is now known as Michigan. He also traded with natives, supplying them with liquor, which was frowned upon by both Simcoe and the local religious authorities.