In the 1821 merger with the North West Company, the Hudson's Bay Company gained control of North West Company trading posts west of the Rocky Mountains. They established headquarters at Fort George (formerly Astoria). George Simpson, Governor of Hudson's Bay Company, visited the Columbia District in 1824-25, journeying from York Factory. He investigated a quicker route than previously used, following the Saskatchewan River and crossing the mountains at Athabasca Pass. This route was thereafter followed by the York Factory Express brigades.