The Greenock Swamp is southern Ontario's single largest forested wetland at approximately 8,094 hectares (20,000 acres) in size. Saugeen Conservation owns approximately half of this vast wetland, a total of 3,439 hectares.
In addition to being a Class 1 Wetland, the swamp is noted for its size, history and ability to act as a giant sponge, releasing water during periods of drought and absorbing water during heavy rainfall. The Authority began purchasing property in this area as early as the 1950's.
The swamp was noted historically for its vast stands of White Pine. A man by the name of Henry Cargill purchased a large tract of the swamp in 1879 and began serious logging operations, that spanned over the next 25 years. Large canals were dug through the swamp to float logs down to the Village of Cargill (named after Henry), for processing and shipping.