The US does not use imperial units. Imperial units are those defined in the British Weights and Measures Act of 1824. What the US uses is the US customary syste

The US does not use imperial units. Imperial units are those defined in the British Weights and Measures Act of 1824. What the US uses is the US customary system, where units have the same name as the Imperial ones, but not the same values. Now, the US customary units are defined in terms of SI units anyway, just with annoying, non-integer conversion factors.