4 US physical features that are historically important (bodies of water, climate regions, mountains..etc)?

Question

I already have the Appalachian Mountains and the Mississippi River, but can't think of anything else.

Answer 1

The grate lakes,The Rockie Mountains. The Bad Lands.

Answer 2

The key to your answer is HISTORICALLY important, and not simply geographic.

What about the 49th Parallel?  Remember the slogan of Democratic presidential candidate James Polk in 1844, "Fifty-Four Forty or Fight!" which refers to the dispute between the U.S. and Britain over the northern boundary between the U.S. and British North America (now Canada).  The U.S. claimed territory to 54 degrees, 40 minutes north latitude.  The British claimed ownership all the way south to 42 degrees north latitude.  The Oregon Treaty of 1846 compromised on the 49th parallel.

How about the Rio Grande river?  It also became the southern boundary between Texas and Mexico in 1848.  

The Erie Canal became historically important for trade reasons by connecting the midwest with the eastern seaports.

The Cuyahoga River in Ohio is historically important because it caught fire in 1969 due to the pollutants in it, which helped lead to the environmental movement and the creation of the Clean Water Act in 1972.

That's all I can think of for now.

Answer 3

What about the Nile river in Egypt? See the source below... Also, just simply do a Google search. I searched for "important physical features" and saw several links...  

Answer 4

The Great Lakes

The Great Plains

The Rocky Mountains

The Great Basin