Newmarket, Ontario in the context of "Regional Municipality of York"

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.

As of the 2021 census, York Region's 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 three largest cities in York Region are Markham, Vaughan and Richmond Hill.

The Holland River is a river in Ontario, Canada, that drains the Holland River watershed into Cook's Bay, the southern extremity of Lake Simcoe. The river flows generally north, and its headwaters lie in the Oak Ridges Moraine. The Holland River watershed is approximately 600 square kilometres (230 mi), spanning an area that includes New Tecumseth, King Township, Newmarket, Aurora, East Gwillimbury, and Whitchurch-Stouffville. The river's watershed also contains the Holland Marsh, a fertile farmland region renowned for its vegetable production.

The river was originally known as Micicaquean Creek, its indigenous name. It was renamed by Lieutenant-Governor Simcoe after Captain Samuel (Johannes) Holland, (1729–1801), Dutch-born first Surveyor General of British North America.