To the south stand the Oregon Buttes, a major trail landmark. Their name is significant because the buttes were roughly the beginning of the Oregon Territory and helped keep emigrants encouraged, even though there were still hundreds of miles of rough going ahead. Today, the Oregon Buttes are an Area of Critical Environmental Concern because of their cultural significance and important wildlife values. About twelve miles to the southwest of Oregon Buttes is the Tri-Territory site, where the Oregon Territory, Mexican Territory, and Louisiana Purchase had a common boundary. The large landmark just to the south is Pacific Butte. The great height and mass of the butte, combined with a ridge to the north paralleling the emigrant trails, helps create a visual channel through which travelers migrated on their way through South Pass.