Duncan Macmillan (February 11, 1837 – April 21, 1903) was a lawyer, judge and political figure in Ontario, Canada. He represented Middlesex East in the Canadian House of Commons from 1875 to 1887 as a Liberal-Conservative member.[1]
He was born in London Township, Upper Canada,[1] the son of William Macmillan, and was educated at Queen's University. Macmillan studied law with Sir John A. Macdonald and was called to the bar in 1861.[2] He practised law in London, Ontario.[3] He was elected to the House of Commons in an 1875 by-election held after Crowell Willson was unseated.[1] In 1873, he was named a judge in the court for Haldimand County. Macmillan died at the age of 66 in London, Ontario while still a judge.[3]