Thomas Mears and David Pattee, two Americans, entered into a partnership in 1805 to harness the power of the lower Ottawa River and built the first sawmill on the Upper Canada side of the river. The town of Hawkesbury developed around this mill. Mears also built the Union, the Ottawa River's first steamer. Demand for timber during the Napoleonic Wars created a boom. The mill complex continued to grow for at least the next half century, and by 1870 it included 145 different saws and created over 35 million board feet of lumber per year.