Ookwemin Minising (pronounced Oh-kway-min Min-nih-sing) is a 39.6 hectares (98 acres) artificial island in Toronto's Port Lands. It is bordered by the Keating Channel to the north, the Don River to the east and south, and Toronto Harbour to the west.

Ookwemin Minising was formed in the 2020s as part of Waterfront Toronto's flood protection and revitalization efforts in the Port Lands. As part of the project, the mouth of the Don River was rerouted and naturalized, extending it south and west into the Port Lands. This reconfiguration led to the creation of the island.

The area now called Ookwemin Minising has been known by several names since the Port Lands revitalization project began, including the Lower Don Lands, River Precinct, Cousins Quay, reflecting various phases of planning. From about 2014 to 2024, it was referred to as Villiers Island. The planning name originated from Villiers Street, a key street on the island named in the early 20th century after Villiers Sankey (1854-1905), a former City Surveyor for Toronto. Villiers Street will continue to be a prominent street on the island. In November 2024, to mark the creation of the new island, the City of Toronto officially adopted the name Ookwemin Minising as part of the Port Lands Indigenous Place Naming Initiative.

The naming involved an Indigenous Advisory Circle, which included Elders, Knowledge Keepers, language speakers, youth, and cultural leaders. The Advisory Circle brought together representatives from Anishinaabe, Haudenosaunee, and Métis backgrounds. Participants represented several nations, such as the Mississaugas of the Credit First Nation, Williams Treaty First Nations (including the Mississaugas of Curve Lake, Alderville, Hiawatha, and Scugog Island), Chippewas of Lake Simcoe (Beausoleil, Georgina Island, and Rama), Six Nations of the Grand River, and the Métis Nation of Ontario.

This name reflects the Anishinaabemowin (Ojibwe) tradition of naming places after local flora and landscape features, as seen in other local names like "Adoobigok" (the place of the alders) near the Etobicoke Creek. Black cherry trees historically grew along the waterfront, connecting Toronto’s new island to its natural past and restoring these trees was seen to symbolize the revitalization of native ecosystems. Many black cherry trees are being planted on the island.

The initiative focused on honoring the historical and cultural significance of Indigenous peoples, particularly the traditional caretakers of the land, through the selection of a new name.

According to the Don Mouth Naturalization and Port Lands Flood Protection Project – Archeological Assessment of Existing Conditions, black cherry trees were among the species found in the complex ecosystem surrounding the lower Don River. This region supported a patchwork of diverse plant communities, including dry uplands and wet lowlands, which fostered a rich coastal wetland ecosystem comparable to other Great Lakes areas like Long Point on Lake Erie.

The island was first part of the "Ashbridge's Bay" wetlands around the original mouth of the Don River, connected to a sandbar that is now the Toronto Islands. By the turn of the 20th century, the marsh had become polluted, and the city filled it with landfill, and devoted it to industrial purposes. Some of the early twentieth century landfill was polluted, contaminated with heavy metals or toxic chemicals. The industrial enterprises were also polluting, including acres of petroleum tank farms and berms of road salt.