Cootes Paradise is a property with many boundaries, but is primarily a property of the Royal Botanical Gardens at the western end of Lake Ontario, but is also remnant of the larger 3700 acre Dundas Marsh Crown Game Preserve established by the province of Ontario in 1927., dominated by a 4.5 km long rivermouth wetland, representing the lake's western terminus. It is found on the west side of Hamilton Harbour and is located in the municipality of Hamilton, Ontario, Canada. Cootes Paradise Environmentally Sensitive Area is larger "core area" within the City of Hamilton's Natural Heritage System and has a very similar boundary to the original Dundas Crown Game Preserve.

Hamilton Harbour lies on the western tip of Lake Ontario, bounded on the northwest by the City of Burlington, on the south by the City of Hamilton, and on the east by Hamilton Beach and Burlington Beach. It is joined to Cootes Paradise by a narrow channel formerly excavated for the Desjardins Canal. Within Hamilton itself, it is referred to as "Hamilton Harbour", "The Harbour" and "The Bay". The bay is naturally separated from Lake Ontario by a sand bar. The opening in the north end was filled in and channel cut in the middle for ships to pass. The Port of Hamilton is on the Hamilton side of the harbour.