The Otter Tail River long played a vital role in the development of Fergus Falls by supporting flour mills, saw mills, and power plants. Early maps identified the river as the Red River, and Ojibwe Indians called it "Otter Tail" as far north as Grand Forks, North Dakota; the official name changed around 1907. In 1857, while seeking potential townsite locations along the river, Joe Whitford was told by a group of Ojibwe that there was "big swift water" in this area. Seeing the potential to harness the rapids for power, Whitford named the site after his employer, James Fergus. As the river turns through Fergus Falls, its westerly flowing waters fall approximately ninety-five feet. During his 1848 geological survey of Minnesota, American geologist David Dale Owen described this stretch of river as turbulent rapids where canoes shot down with unstoppable velocity and ran hard and fast among the rocks in water up to the men's armpits.