The lyrics for this old standard were written by school teacher George Washington Johnson from Hamilton, Ontario. Margaret "Maggie" Clark, (only three years his junior) was his pupil. The mill in question was near Binbrook. The poem was published in 1864 in a collection entitled "Maple Leaves". George and Maggie were married October 21, 1864, but Maggie's health deteriorated and she died on May 12, 1865. American, James Austin Butterfield set the poem to music a few years later. It has been sung ever since. The melody is also sometimes played as a schottische and used for the Canadian Progressive Barn Dance. John McCormack sings it in 1925 in the YouTube link below. There are lots of other versions as well.