Mima-type soil mounds result from the repeated outward tunneling of Geomyid pocket gophers from nest and food storage centers and the resultant backward displacement of soil and its accumulation near such centers. These mounds are widespread in alpine and montane grassland habitats in the western United States. Their abundance in highland areas is confirmed by Google Earth surveys, by published studies and other sources, and by personal fieldwork of the author and colleagues. Highland areas in Canada and Mexico were also surveyed by Google Earth, but Mima-type mounds have not yet been found in these locations. Almost all alpine mound sites surveyed are on ridge tops or south-facing slopes, with many best expressed just above timberline. In some northern locations alpine and montane mounds appear to have formed since the Pleistocene. The presence of mounds only on moraines of Illinoian age at one Wyoming site suggests that mounds there, and thus perhaps in more southern locations, may have begun forming much earlier.