Horn River formed along the middle course of the Horn River, and is followed downstream by the "Second Lake". The river turns south-west, where the "Mink Lake" is formed along its course. The Laferte River also flows into the Mink Lake. Horn River then flows south, and it receives the waters of the Bluefish River before it empties into the Mackenzie River, downstream from the Great Slave Lake), immediately upstream from Mills Lake, at an elevation of . The arch made by the river defines the "Horn Plateau", a flat elevated area that rises up to ) to the north and east,
Mackenzie River with sternwheelers transporting passengers, domestic supplies and industrial goods from as far upstream as the Athabasca River all the way to the delta, though with several areas such as the huge rapids on the Slave River requiring portages. The route taken by gold seekers started in Edmonton and followed the Athabasca, Slave and Mackenzie Rivers as far as the Peel River, then up the Peel and its tributary the Rat River to the headwaters of the Porcupine River, which flows to the Yukon River. Many who attempted the journey died along the way or turned back before reaching the Yukon.