Delta is a city in the Lower Mainland region of British Columbia, Canada, as part of Greater Vancouver. Located on the Fraser Lowland south of Fraser River's south arm, it is bordered by the city of Richmond on the Lulu Island to the north, New Westminster to the northeast, Surrey to the east, the Boundary Bay and the American pene-exclave Point Roberts to the south, and the Strait of Georgia to the west.

The Lower Mainland is a geographic and cultural region of the mainland coast of British Columbia that generally comprises the regional districts of Metro Vancouver and the Fraser Valley. Home to approximately 3.05 million people as of the 2021 Canadian census, the Lower Mainland contains sixteen of the province's 30 most populous municipalities and approximately 60% of the province's total population.