Final answer:
The North American Plate and Pacific Plate are the two plates that affect the United States. The North American Plate covers most of the country and is responsible for the creation of landforms like the Rocky Mountains. The Pacific Plate is located along the western coast and causes tectonic activity.
Step-by-step explanation:
The two plates that affect the United States are the North American Plate and Pacific Plate.
The North American Plate covers most of North America, including the United States. It is responsible for the creation and shaping of many landforms in the region, including the Rocky Mountains. The Pacific Plate is located along the western coast of North America and is associated with tectonic activity, such as earthquakes and volcanic eruptions.
Learn more about Plate Tectonics