The United States
The U.S. is located in the center of the North American continent.  It is bordered by Canada to the north, and Mexico to the south. On the east is the Atlantic Ocean, and on the west, is the Pacific Ocean.  In addition to the 48 continental states, Alaska and Hawaii are included, for a grand total of 50 states.

For the sake of comparison, all of the land area in North America totals 13,408,433 square miles.  Of that, the United States alone accounts for 5,983,517 square miles. That means the U.S. occupies just less than half (almost 45%) of continent!  It also means that the United States is the third-largest country on earth (by size), right behind Russia and Canada.

According to 2001 Census figures, the U.S. population measured nearly 285,000,000 people. So, not only are we the third-largest in size (behind China and India), but we are also the third-largest nation if measured by population.

U.S. Climates and Regions

Most of the United States has a temperate climate, but Hawaii and Florida are tropical, Alaska is polar/arctic, the Great Plains region is semiarid (dry, almost desert-like), and the Great Basin of the southwest is an arid (desert-like) climate.

The U.S. can be divided into many different regions (areas that share some common characteristics).  By clicking on the map to the left, you can see the United States divided into five geographic regions: The Western Mountains & Basins, the Great Plains, the Central Lowlands, the Appalachian Mountains, and the Atlantic Coastal Plain. This is only one way to classify the very diverse areas of America.

Not only does it have very different geographic regions, but the U.S. has a huge array of  natural resources such as timber, coal, petroleum, and natural gas.  In addition, it has large metal deposits of copper, lead, uranium, gold, iron, nickel, silver and zinc. As you can imagine, the mining industry in the U.S. is extensive.

From the non-agricultural, arid land in the southwest, to the fertile central lowlands and coastal plains, there is an extremely variable array of landforms and land usage in the United States.  The map to the right highlights two dozen different vegetation zones in the U.S. and North America.

Barriers to Expansion

One of the greatest obstacles for early settlers intent upon moving westward, were the Appalachian Mountains.  They extend, in an almost unbroken chain, from Maine to Alabama, with very few places to pass through.  Early settlers quickly found the Cumberland Gap (at the junction of modern-day Kentucky, Tennessee and Virginia) to be one of the easiest ways westward (and inland) from the colonies.

Four hundred miles west of the Cumberland Gap, settlers would encounter the largest river in North America,  At that point, the 2,552 mile long Mississippi River was nearly one mile wide, and over 100 feet deep.  Travelers had to go miles upstream to find a ford (a place to cross the river).

Once across the Mississippi River, the Great Plains made for fairly easy travel.  It was not until settlers saw the Rocky Mountains, that westward expansion slowed.  Most people were diverted either far to the south, or chanced high passes through the mountains, sometimes getting stranded in unpredictable winter snowstorms. Of course, early Spanish settlers had been venturing inland from the sixteenth century, and had made many contacts with the indigenous peoples of the southwest.