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. The 2021 census population was 1,173,334, with a growth rate of 5.7% from 2016. The Government of Ontario expects its population to surpass 1.5 million residents by 2031. The largest cities in York Region are Markham, Vaughan and Richmond Hill. History At a meeting in Richmond Hill on May 6, 1970, officials representing the municipalities of York County approved plans for the creation of a regional government entity to replace York County. The plan had been presented in 1969 by Darcy McKeough, the Ontario Minister of Municipal Affairs, taking about a year to determine municipal boundaries within the new regional government. The Regional Municipality of York was created by Act of the Legislative Assembly of Ontario in 1970 (Bill 102 An Act to Establish The Regional Municipality of York), which took effect on January 1, 1971. The creation of the regional municipality resulted in the consolidation of the fourteen former municipalities of York County into nine new municipalities: The township of Whitchurch merged with the town of Stouffville to create the town of Whitchurch–Stouffville, ceding land to Aurora, Newmarket, and Richmond Hill to the west of the proposed Highway 404 and annexing a northern strip of land from the township of Markham. The western boundary of the new town of Markham was defined to be at Yonge Street, where its northern boundary was formed with Richmond Hill (to which it ceded land) and its western boundary with the new town Vaughan. The new town of Vaughan would consist of all communities in the area bounded by Markham and Richmond Hill in the east, Metro Toronto in the south, the periphery of the regional municipality in the west, and the new township of King in the north. The townships of Georgina, North Gwillimbury, and Sutton were merged into the township of Georgina, and the East Gwillimbury neighbourhood of East Gwillimbury Heights was merged into Newmarket. King formed the northwestern part of the new region, but the