The lands that include Jokers Hill were originally assembled by Colonel RS McLaughlin, founder of the Canadian arm of General Motors. In 1952, he gave the estate to his daughter Billie and her husband, Major General Churchill Mann. The couple managed a thoroughbred racing and breeding operation on the site, and built an extensive trail system.

After passing through several hands, the property was purchased by Drs. Murray and Marvelle Koffler in 1969. Kofflers retained architect Napier Simpson to redesign the main residence, and landscape architect J Austin Floyd to reconfigure the grounds and ponds.

In 1995, the Kofflers donated their 350-hectare equestrian estate, Jokers Hill, to the University of Toronto. The gift made the University one of the largest landowners on the Oak Ridges Moraine—and steward of a site of regional, provincial and national significance.

In the spring of 1996, scientists and students from the University of Toronto headed north to a new property, the Koffler Scientific Reserve at Jokers Hill. There, atop the Oak Ridges Moraine, they found a landscape carpeted with opportunity. The natural and agricultural ecosystems on the site offered tantalizing prospects for studies in biodiversity, ecology, evolution and conservation science. The property’s proximity to the campuses meant that students would have ready access to a place where they would not just learn about science, but where they could do science. In the years since, the Koffler Scientific Reserve at Jokers Hill has become an internationally recognized facility, with a distinguished record of research, training and public education.