Born in either 1832 or 37 in Scotland comes Duncan McMillan to Dundas in 1846.
At first a brass moulder, McMillan became a Dundas photographer from 1868 to 1887 before becoming a grocer. Duncan was an excellent artist which contributed to his work as a photographer.
At the same time, he was the owner of a confectionery store and had claimed to be founder of Mechanics institute and was the secretary and librarian.
The son of John McMillan and Joan Cumming, Duncan McMillan had married Elizabeth Fisher with whom he had two children with Hiram Rufus McMillan and Mary McMillan.