Fill in all the gaps, then press "Check" to check your answers. Use the "Hint" button to get a free letter if an answer is giving you trouble. You can also click on the "[?]" button to get a clue. Note that you will lose points if you ask for hints or clues!
Appalachian Mountains Atlantic Ocean Basin and Range Canadian Shield Coastal Plain Coastal Plains Coastal Range Colorado River Columbia River eastern Canada Great Lakes Great Plains Gulf of Mexico horseshoe Hudson Interior Lowlands Mississippi River and the Missouri River Ohio River Pacific Ocean Rio Grande Rocky Mountains