The Churchill River is a major river in Alberta, Saskatchewan and Manitoba, Canada. From the head of the Churchill Lake it is 1,609 kilometres (1,000 mi) long. It was named after John Churchill, 1st Duke of Marlborough and governor of the Hudson's Bay Company from 1685 to 1691. The Cree name for the river is Missinipi, meaning "big waters". The Denesuline name for the river is des nëdhë́, meaning "Great River".

Saskatchewan is a province in Western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and to the south by the United States. Saskatchewan and Alberta are the only landlocked provinces of Canada. In 2023, Saskatchewan's population was estimated at 1,225,493. Nearly 10% of Saskatchewan's total area of 651,900 km2 (251,700 sq mi) is fresh water, mostly rivers, reservoirs, and lakes.