what is the major geographical feature that dominates the western part of the central region of the us?

The major geographical feature that dominates the western part of the central region of the United States is the Great Plains. This feature is the dominant landscape in that area, characterized by vast flat lands and prairies extending through the western part of the central U.S. region. This contrasts with the Rocky Mountains, which dominate more the western U.S. region overall, but for specifically the western part of the central region, the Great Plains are more prominent. Thus, the answer you're looking for is the Great Plains.