The geological feature that separates the Rocky Mountains from the Great Plains is the escarpment.

The escarpment serves as a significant geological boundary between the Rocky Mountains and the Great Plains. This steep slope or cliff delineates the transition from the rugged, towering peaks of the Rockies to the flat and expansive terrain of the plains. The escarpment is characterized by a dramatic elevation change, which influences local ecosystems and weather patterns. It supports a diverse range of flora and fauna that adapt to the varying conditions on either side. The region is not only important for its geological features but also serves as a vital area for water drainage and wildlife migration, enhancing the ecological richness of both the mountains and the plains.