| A | B |
|---|
| Ohio River | Gateway to the West |
| Missouri River | tributary of Mississippi, transported farm and industrial products |
| Mississippi River | transported farm and industrial products, flows into Gulf of Mexico |
| Atlantic Ocean | highway for explorers, settlers, and immigrants |
| Pacific Ocean | early exploration route |
| Columbia River | explored by Lewis and Clark |
| Colorado River | explored by the Spanish |
| Rio Grande | forms the border with Mexico |
| St. Lawrence River | forms the NE border with Canada, connects the Great Lakes to the Atlantic Ocean |
| Gulf of Mexico | transportation route to Mexico and other parts of America, used by French and Spanish |
| Great Lakes | allowed inland port cities to grow in the midwest |
