The two regions that are named because of the physical features that are common to the group of states are:

1. The Great Plains: This region is named for the vast, flat, and mostly treeless grasslands that dominate its landscape. It stretches from the Canadian border in the north to the Mexican border in the south, and from the Rocky Mountains in the west to the Mississippi River in the east.

2. The Appalachian Mountains: This region is named after the Appalachian Mountain range, which runs along the eastern edge of North America, from southern Canada to northern Alabama. The mountains are a defining feature of the region and have influenced its culture, economy, and way of life.

Let me know if you'd like to learn more about either of these regions!