The Sweet Grass Hills are a group of three separate laccolithic centers in the northern part of Toole County, Montana, and almost touching the international boundary. All three rise abruptly from the plains at a distance of approximately 100 miles east of the Rocky Mountains. The summits at the maximum are nearly 3,000 feet above the neighboring plains and are striking landmarks, even when viewed from the railway train at a distance of 40 or 50 miles. As a result of observations made in 1873–74, Dr. George M . Dawson2 records that these isolated mountains were called by the half-breed hunters “Montagues du Foin de Senteur,” and by the traders of the Missouri region the “Sweet Grass Hills.” On the maps of that time they were also named “Three Buttes.” Today the name Sweet Grass Hills seems well established and in general usage.
Figure 1.— Map of the . . .