The land for Oakville/St. Mary's Cemetery was donated in 1858 by the first mayor of Oakville, George K. Chisholm. The land was surveyed by George C. Tremaine, whose Map of Halton County, Canada West appeared the same year. After clearing the trees, the land was surrounded by a white picket fence and a line of hitching posts was placed on Sixth Line. Pines that still exist in the cemetery today were planted along the road. A sale of lots was held at Town Hall and those purchased were marked with little white stakes bearing the names of the owners.
Chisholm suggested the old cemetery on Reynolds Street, north of Palmer Avenue, be moved to the new town cemetery to make way for a public school. The removal of remains from the old cemetery began immediately, though the task was not completed for more than 20 years. In 1881, the last 16 bodies were disinterred from the old cemetery and moved to the Oakville/St. Mary's Cemetery, creating considerable interest among the residents at the time.
The founder of Oakville, Colonel William Chisholm, and members of his family are buried in Oakville/St. Mary's Cemetery.
Burials in existing plots in Oakville/St. Mary's cemetery are still being carried out today, though no new plots are being sold.