The Grass River is a historically important waterway in the Hudson Bay drainage basin in the Northern Region of Manitoba, Canada.

The river was a critical route for earlier European explorers and was part of the "Upper Tract" of the fur trade into Canadian interior.

[10] The Grass River was originally inhabited by people of the Shield Archaic tradition who migrated from the present-day Northwest Territories 5,000 years ago.

[11] The first recorded Europeans to travel the Grass River were the Hudson's Bay Company fur traders and explorers Joseph Smith and Isaac Batt.

In the summer of 1794, surveyor and explorer David Thompson travelled up the Grass River for the first of many times in his career mapping the interior of North America.

[17] The Grass River is a popular wilderness canoe route due to its pristine state, Indigenous rock paintings, scenic waterfalls, and sport fishing.

[18] A trip down the full length of the river can take up to three weeks, but most canoeists travel shorter sections such as the Cranberry Portage to Split Lake route.