1. Geographical position.

The United States of America is the world's third largest country with an area of 9.6 million square kilometers, the population — over 300 million people (2007). Most of the country is in the central part of North America. It is bordered by Canada on the north and Mexico on the south, the Atlantic Ocean to the east and the Pacific Ocean to the west.

Due to its geographical position and administrative division the United States is one of the few fragmented countries in the world. Of the fifty states of the country forty-eight states are conterminous, or enclosed within one common boundary. The other two states, Alaska and Hawaii, are located apart from the rest of the country. Alaska is locat¬ed in the far northwestern part of North America, bordering western Canada. Hawaii is in the Pacific Ocean to the south and west of mainland North America. The United States occupies a favourable geographical position. The Atlantic Ocean is of great importance for the country's sea communications with Europe, Africa and South America. The sea routes to Asia and Australia pass over the Pacific Ocean. The sea route through the Panama Canal, which connects the two oceans, runs over the Gulf of Mexico and the Caribbean Sea.

The physical geography of the United States is as varied as that of any other coun¬try in the world. There are huge forests, large areas of flat, grassy plains, and deserts. An average elevation of about 762 meters masks some great variations. These variations range from a low of 86 meters below sea level in California to a high of over 6,000 meters above sea level in Alaska.

The people of the United States are descended from many, many different groups of people from around the world. It is a country of immigrants. The first inhabitants came from Asia, crossing the Bering Strait into Alaska during the last Ice Age. Almost 40,000 years later, Spanish adventurers entered what is now the southwestern United States by way of Mexico. From that time, migrations have continued — Europeans, Africans, Asians, and other people from the Americas entering the country to live and work, adding their cultures to that of the nation.

The United States is spread over a huge area of the Western Hemisphere. For exam¬ple, the total distance between the most eastern Florida Key and most western island of Hawaii is 9,418 kilometers. The conterminous United States stretches some 4,664 kilo¬meters from Maine in the east to California in the west. From the northern border of North Dakota to the southern border of Texas, it is 2,585 kilometers.

It is little wonder that within a country so large there can be found so many different landscapes.

The country can be divided from the point of view of physical geography into nine regions. These are: (1) the Coastal plains, (2) the Appalachian Highlands, (3) the Interior Plains, (4) the Interior Highlands, (5) the Rocky Mountains, (6) the Intermontane Plateaus and Basins, (7) the Pacific Coastal Ranges, (8) Alaska, and (9) Hawaii.

2. The physical geography of the United States

The Coastal Plains

A lowland area sweeps from Massachusetts to Texas along the coasts of the Atlantic Ocean and the Gulf of Mexico. This coastal plain, which extends for more than3,219 kilometers is divided into two parts — the Atlantic Coastal Plain and the Gulf Coastal Plain. The Atlantic Plain follows the coastline of the Atlantic Ocean south from Cape Cod in Massachusetts to the Florida Peninsula. The coastline is irregular. Many natural harbours have been created. Some of the more important ones are Massachusetts Bay, New York Bay, Delaware Bay, Chesapeake Bay, and Long Island Sound.

The Gulf Plain is a much wider band of flat land and gently rolling hills. It varies in width from 241 kilometers to about 966 kilometers. At one point, the plain extends far inland to where the Ohio River flows into the Mississippi River. The Mississippi, the longest river in North America, empties into the Gulf of Mexico in Southern Louisiana. There it has made a huge delta. This part of the Gulf Coastal Plain is made up of marsh¬es and bayous — a word used to describe the many small, marshy creeks and rivers that flow through the delta area.

The Appalachian Highlands

Just west of the Atlantic Coastal Plain is the Appalachian Highlands. This region takes its name from the Appalachian Mountains. The highlands stretch about 1,931 kilo¬meters in the United States from northern Maine to central Alabama. They lie in a north¬east to southwest direction. In the highlands is the highest peak in the eastern United States — Mount Mitchell in western North Carolina. It rises 2,037 meters above sea level.

The eastern edge of the highlands is known as the Piedmont. This low plateau varies in altitude from 152 to 305 meters above sea level. West of the Piedmont are the Appalachian Mountains. They are nearly parallel with the Atlantic coast-line.

The Interior Plains

A huge "plain region" covers the middle of the United States between the Appalachian Mountains and the Rockies. The region is divided into Central Plains the Great Plains. The Central Plains include lowland parts of central and western Kentucky and Tennessee, the Great Lakes area, and the upper Mississippi and lower Ohio and Missouri river basins. West of the river basins is the area of the Great Plains. Many long rivers flow eastward from the Great Plains, emptying into the Mississippi.

The Interior Highlands

Two separate highlands regions rise above the plains in the central United States. These are the Superior Highlands and the Ozark Plateau.

Located around Lake Superior, in the northern parts of Minnesota, Wisconsin, and Michigan, the Superior Highlands are actually a part of the Canadian Shield. Coniferous forests cover rocky plateaus. There are many lakes among the hills. The Ozark Plateau is located between the Missouri and Arkansas rivers west of the Mississippi River. The land is gently rolling in places with some rugged mountains in other places.

The Rocky Mountains

West of the Great Plains is the Rocky Mountain region. The Rocky Mountains extend from Canada south to New Mexico and Western Texas. The region occupies an area over 1,600 kilometers long, it varies in width between 200 to 600 kilometers.

The Rockies stretch from north to south. The Rocky Mountains are much more rugged and much higher than the Appalachians. Many peaks are over 3,658 meters high. Plants are greatly affected by altitude. Mountain tops not covered by snow are capped by tundra grasses and mosses.