Dawson joined the Geological Survey of Canada (GSC) in 1875 and led many field parties in Canada's north and west. His work is credited as having laid the foundations of much of our knowledge of the geology and natural history of these regions. For example, during 1883 and 1884, Dawson travelled through the Canadian Rockies where he mapped out the major mountains, mountain passes, and rivers. Some of the many peaks he charted were Mount Assiniboine, , and Mount Temple, . As a result of his field research, a map of his work was published in 1886 covering the Canadian Rockies from the U.S. border to the Red Deer River Valley and Kicking Horse Pass.