Greendale is a predominantly agricultural community in Chilliwack, British Columbia, Canada, 92 kilometres (57 miles) east of Vancouver. Greendale is located on the west side of Chilliwack, abutting the city of Abbotsford to the east. The Vedder River separates Greendale from Yarrow, which is located to the south. Greendale was renamed Sumas in 1951 to avoid confusion with the adjacent municipality, the District of Sumas (now part of the City of Abbotsford), as well as Sumas, Washington. At the base of Sumas Mountain, there was once a 10,000-acre (4,000-hectare) lake. In the early 1920s, Sumas Lake was drained. Greendale saw two significant floods after the drainage was completed, in 1894 and 1948.
Greendale is home to the Great Blue Heron Nature Reserve.