Windmills feature uniquely in the history of New France, particularly in Canada, where they were used as strong points in fortifications. Prior to the 1690 Battle of Québec, the strong point of the city's landward defenses was a windmill called Mont-Carmel, where a three-gun battery was in place. At Fort Senneville, a large stone windmill was built on a hill by late 1686, doubling as a watch tower. This windmill was like no other in New France, with thick walls, square loopholes for muskets, with machicolation at the top for pouring lethally hot liquids and rocks onto attackers. This helped make it the "most substantial castle-like fort" near Montreal.
In the United States, the development of the water-pumping windmill was the major factor in allowing the farming and ranching of vast areas of North America, which were otherwise devoid of readily accessible water. They contributed to the expansion of rail transport systems throughout the world, by pumping water from wells to supply the needs of the steam locomotives of those early times. Two prominent brands were the Eclipse Windmill developed in 1867 (which was later bought by Fairbanks-Morse) and the Aermotor, which first appeared in 1888 and is still in production. The effectiveness of the Aermotor's automatic governor, which prevents it from flying apart in a windstorm, led to its popularity over other models. Currently, the Aermotor windmill company is the only remaining water windmill manufacturer in the United States. They continue to be used in areas of the world where a connection to electric power lines is not a realistic option.
The multi-bladed wind turbine atop a lattice tower made of wood or steel was, for many years, a fixture of the landscape throughout rural America. These mills, made by a variety of manufacturers, featured a large number of blades so that they would turn slowly with considerable torque in low winds and be self regulating in high winds. A tower-top gearbox and crankshaft converted the rotary motion into reciprocating strokes carried downward through a rod to the pump cylinder below.
Windmills and related equipment are still manufactured and installed today on farms and ranches, usually in remote parts of the western United States where electric power is not readily available. The arrival of electricity in rural areas, brought by the Rural Electrification Administration (REA) in the 1930s through 1950s, contributed to the decline in the use of windmills in the US. Today, the increases in energy prices and the expense of replacing electric pumps has led to an increase in the repair, restoration and installation of new windmills.