Newmarket (2006 Population: 74,295, 2008 estimate: 80,400) is a town in Southern Ontario located approximately 25 km north of Toronto, Ontario, Canada. It is part of the Greater Toronto Area and the Golden Horseshoe in an area known as the "905 Region" (a reference to the GTA's telephone area code outside Toronto proper). Newmarket is well connected by highway to the Toronto area, served by two interchanges along Highway 404 and connected to Highway 9. Newmarket is the seat of the County Courthouse of the York Region. Southlake Regional Health Centre (hospital) is located in Newmarket.

Newmarket's geographical coordinates are 44.05°N, 79.46°W, and its elevation above sea level is 239 m. It has an area of 38.07 km². The town is bounded on the north by the Town of East Gwillimbury, on the east by the Town of Whitchurch-Stouffville, on the south by the Town of Aurora, and on the west by King Township, themselves all likewise part of York Region.

Newmarket lies north of the Oak Ridges Moraine. Hence, all drainage in the town flows northwards into Lake Simcoe. The main river in Newmarket is the East Holland River (known locally simply as the Holland River), and all other streams in the town are tributary thereto. These include Bogart Creek, a brook that wends its way into town from the moraine by way of Bogarttown emptying into the Holland in north-central Newmarket, Western Creek, another brook rising just west of town and reaching the Holland in the town's north end, Tannery Creek, a stream that joins the Holland in south Newmarket after flowing through Aurora, and a number of other small watercourses. From Wikipedia, the free encyclopedia.