Mills An English surname. It is most likely derived from ‘dweller by the mills’, or perhaps a patronymic, from Miles or Mill. In 1890 Mills was principally found in Antrim, and the estimated number of bearers was 2,640. In the United States it is the 152nd most numerous surname with an estimated 167,750 bearers. In England and Wales in 1996 it was the 88th most numerous surname.