Barrie is a city in Southern Ontario, Canada, about 90 kilometres (56 mi) north of Toronto. The city is within Simcoe County and located along the shores of Kempenfelt Bay, the western arm of Lake Simcoe. Although physically in Simcoe County, Barrie is politically independent. The city is part of the extended urban area in southern Ontario known as the Greater Golden Horseshoe. As of the 2021 census, the city's population was 147,829, while the census metropolitan area had a population of 212,667 residents.

The area was first settled during the War of 1812 as a supply depot for British forces, and Barrie was named after Sir Robert Barrie. The city has grown significantly in recent decades due to the emergence of the technology industry. It is connected to the Greater Golden Horseshoe by Ontario Highway 400 and GO Transit. Significant sectors of the city's diversified economy include education, healthcare, information technology and manufacturing.

Barrie is situated on the traditional land of the Wendat and Anishinaabeg peoples.[10] At its inception, Barrie was an establishment of houses and warehouses at the foot of the Nine Mile Portage from Kempenfelt Bay to Fort Willow, an indigenous transportation route that existed centuries before Europeans arrived in Simcoe County. The portage linked Kempenfelt Bay through Willow Creek, connecting Lake Simcoe to the Nottawasaga River which flows into Georgian Bay off Lake Huron.