The USA stretches from Canada to Mexico and from the Atlantic to the Pacific Ocean covering an area of about nine and half million square kilometres.
Two of the States are separated from the mainland:
– ALASKA lies north-west of Canada
– HAWAII ISLANDS lie in the north Pacific Ocean, 3000 km off the west coast.
The USA also includes island territories:
– in the Carribean PUERTO RICO
– in the Pacific MIDWAY ISLANDS
– in the Bering Sea ALEUTIAN ISLANDS
Being 4600 km coast to coast, the mainland US crosses four times zones:
so there is a 3-hour difference between New York and San Francisco.
2. THE MOUNTAINS
The highest mountains in the US are in Alaska: among them is MOUNT MC KINLEY, the highest point in the country 6190 m.
Three mountain systems run vertically through mainland US:
● The westernmost mountain system includes the COAST RANGES and the CASCADE RANGE which lie along the Pafcific Ocean, the SIERRA NEVADA where MOUNT WHITNEY rises to a height of 4418 m.
Between the Coast Range and the Sierra Nevada lie the fertile valley of California.
Their main range called the Continental Divide separates the rivers flowing into the Pacific from flowing eastwards.
● The eastern mountain system is formed by the APPALACHIANS, a series of chains extending from Maine down to Alabama.
The highest peak in the Appalachians is MOUNT MITCHELL (in North Carolina 2037 m.).
To the east of the Appalachians lies a coastal plan that in the northern states is covered by thick forests.
Between the Rockies and the Appalachians lies a vast lowland: the Interior Plains, divided into two distinct parts:
- CENTRAL LOWLAND: the eastern part - it is crossed by many rivers and the soil is very fertile
- THE GREAT PLAINS: the western part - here the soil is covered by tough grass so that agricolture is limited to the few sections where irrigation has been provided.
In Colorado and New Mexico the Great Plains gradually rise in height becoming plateaus crossed by gorges and canyons such as the famous GRAND CANYON of the Colorado river.
The intermontane regions in UTAH, NEVADA, ARIZONA and NEW MEXICO are largely desert.
The most famous desert in the US is in California: DEATH VALLEY is nearly 100m below the sea level and one of the hottest areas on earth.
The rivers of the US are of enormous importance to the country.
The main rivers flowing into the PACIFIC OCEAN are the
The main rivers flowing into the ATLANTIC OCEAN are the
- HUDSON (New York 's river)
- POTOMAC (Washington's river)
- RIO GRANDE
The MISSISSIPI is the most important in terms of size and length (about 6000 km). It receives almost 250 tributaires, the chief of which is the MISSOURI; then the ARKANSAS and the RED RIVER, all flowing from the Rockies; the ILLINOIS, the OHIO and the TENNESSEE, all flowing from the Appalachians.
The main cities standing on its banks are Minneapolis, St. Louis and New Orleans.
The ARKANSAS is about 2320 km. long.
The COLORADO is one of the longest rivers in the country (2320 km.) and with its tributaries supplies water and hydroelectric power to seven states.
The OHIO 2089 km
The RED RIVER 1955 km.
The COLUMBIA 1942 km.
The SNAKE 1660 km.
The TENNESSEE 1390 km.
5. THE LAKES
- LAKE HURON
- LAKE SUPERIOR
- LAKE MICHIGAN
- LAKE ERIE
- LAKE ONTARIO
Between Lake Erie and Ontario there are the famous NIAGARA FALLS which provide about 4 million kilowatts of electricity to Canada and US.
These five likes are estimated to contain about half of the word's fresh water; tourist from all North America are attracted by the beauty of this area, which is also rich in minerals.
The St Lawrence River connects the lakes with the Atlantic and allows access to the industrial cities throught a system of navigable canals.
In the state of UTAH there is the GREAT SALT LAKE; it is also very large and its water contains a very high percentage of salt.
The US is a vast country with a great variety of climatic conditions:
- SUBARCTIC CLIMATE of Alaska
- SUBTROPICAL CLIMATE of Hawaii, south Florida, to the desert areas in Nevada and California
- CONTINENTAL CLIMATE with hot summers and cold winters but the amount of precipitations is different:
of the Middle and Northern Atlantic States
of the Midwestern states
of the Great Plains states
- ALPINE CLIMATE in the Rocky Mountains
● Along the coast on the Gulf of Mexico summers are warm and humid, winters are quite
temperate thanks to the influence of the warm stream of air coming from the Gulf
● All the south central states in spring are battered by recurring destructive hurricanes.
● Of the Pacific coast states the climate depends on the mountains, distance from the
ocean and latitude. It is generally dry and relatively warm in the south, wetter and colder
in Oregon and Washington.
in Oregon and Washington.
By Nicola Basso, 2LSA