The formation of the Rocky Mountains primarily involved interactions with the North American Plate, specifically through subduction of other plates beneath it.

The Rocky Mountains formed due to tectonic activity involving the North American Plate. During the Laramide Orogeny, the Farallon Plate (an ancient oceanic plate) subducted under the North American Plate at a shallow angle. This subduction caused compression, uplift, and faulting of the North American Plate's crust, leading to the creation of the Rockies. While other plates played a role in the broader tectonic history of the region, it was the North American Plate that was directly deformed to create the mountain range.