William Laidlaw was a fur trader, who next to Kenneth McKenzie was said to have been one of the best.
Born in Scotland in about 1798, Laidlaw, he was trained in the service of the British Fur Companies, before immigrating to America. First arriving in Canada, he made his way to St. Louis, Missouri in 1822, where he joined the Columbia Fur Company. He was soon assigned the post of Fort Tecumseh, which later became Fort Pierre Chouteau in present-day South Dakota, the largest and most important post next to Fort Union, North Dakota.
When the firm merged with the American Fur Company in 1827, he stayed on and in about 1834 became a partner in the Upper Missouri Outfit. Sometimes in charge of Fort Union, he was said to have been a severe taskmaster, and his tyrannical temper often made him unpopular. A great lover of hunting he spent much time in the buffalo chase. Like Kenneth McKenzie, he was a good letter writer and evidently was considered a be one of the most able fur trappers in the business. Somewhere along the line, he married a Sioux woman and the two would have five daughters. Remaining always faithful to her, they retired to Liberty, Missouri, where he built a house. He kept an open door to his friends as long as his money lasted, but when he died in October 1851, he was a poor man.