East Gwillimbury is a town on the East Holland River in the upper-tier municipality the Regional Municipality of York. It is part of the Greater Toronto Area of southern Ontario, in Canada. It was formed by the amalgamation of the Township of East Gwillimbury with all the previously incorporated villages and hamlets within the township. The main centres in East Gwillimbury are the villages of Holland Landing, Queensville, Sharon, and Mount Albert. The Civic Centre are located along Leslie Street in Sharon. The northernmost interchange of Highway 404 is at the North edge of East Gwillimbury, just south of Ravenshoe Road. The hamlets of Holt and Brown Hill are also within town limits.

The Regional Municipality of York, also called York Region, is a regional municipality in Southern Ontario, Canada, between Lake Simcoe and Toronto. The region was established after the passing of then Bill 102, An Act to Establish The Regional Municipality of York, in 1970. It replaced the former York County in 1971, and is part of the Greater Toronto Area and the inner ring of the Golden Horseshoe. The regional government is headquartered in Newmarket.