These detail maps of the Mullan Road are marked on county road maps at a scale of l" = 1 mile. The information giving the location of the Mullan Road was obtained from the township surveys made by the General Land Office, U.S. government. These surveys primarily located the section corners within the township. This was necessary so that land claims or titles could be identified as a particular fraction of a numbered section within a township identified by number and range. Flowing streams and existing roads were also marked on these surveys. Hence, the Mullan Road was noted in most places where it traversed. These surveys were made as early as 1860 for Walla Walla and as late as 1912 for the township on the immediate west side of the Bitterroot Mountains at St. Regis Pass in Idaho. The scale of these survey maps is near to l" = 0.5 mile. Present day roads and towns are not indicated on these so that identification can only be made by transcribing the Mullan Road of the old maps on to present day county road maps.
This archive is courtesy of Mineral County Museum and Historical Society, Superior Montana.