Annacis Island is an island located in the south arm of the Fraser River, in Delta, British Columbia. The island is now mostly industrial, and it contains one of Metro Vancouver's secondary wastewater treatment plants.
The southern part of the island is connected to Delta via the Alex Fraser Bridge, which is part of Highway 91. Connections northward to Richmond and New Westminster are via smaller bridges on Highway 91. At the eastern end of the island there is also the Derwent Way Bridge which connects the island to the Queensborough neighborhood of New Westminster. The island is served by a public bus that connects to 22nd Street Station in New Westminster.
The wider part of the Fraser River south of the island is known as Annieville Channel (upstream) and City Reach (downstream), while the more narrow channel north of the island is Annacis Channel. The eastern (upstream) tip of the island is known as Shoal Point, and the western (downstream) tip as Purfleet Point.