Geography of USA

Location

USA Location Map The United States of America (U.S.A.) is located in North America. It is bound to the north by Canada, to the east by the North Atlantic Ocean, to the south by Mexico, and on to the west by the North Pacific Ocean.

The geographic coordinates of the country are 38 degrees 00 minutes north and 97 degrees 00 minutes west. While the northernmost point of the country is Point Barrow, located in Alaska, the States southernmost point is Ka Lae, situated in Hawaii. West Quoddy is the easternmost point. Head in Maine and Cape Wrangell in Alaska is considered the westernmost point. With the exception of Alaska, the entire country lies between 50 degrees north and 25 degrees north latitude.

The U.S.A. is divided into nine time zones. These are the AST- Atlantic Standard Time (UTC -4), EST-Eastern Stand Time (UTC -5), CST-Central Standard Time (UTC -6), MST-Mountain Standard Time (UTC -7), PST-Pacific Standard Time (UTC -8), AKST-Alaska Standard Time (UTC -9), HAST-Hawaii-Aleutian Standard Time (UTC -10), SST-Samoa Standard Time (UTC -11) and Chamorro Standard Time (UTC+10).


Since 2007, Daylight Saving Time starts for the most part of the States on March's second Saturday at 2 a.m. However, the time reverts every November's first Sunday to standard time again at 2 a.m. With the clock set forward by 1 hour the names of the time zones also change to EDT-Eastern Daylight Time (UTC -4), CDT-Central Daylight Time (UTC -5), MDT-Mountain Daylight Time (UTC -6), PDT-Pacific Daylight Time (UTC -7), AKDT-Alaska Daylight Time (UTC -8), HADT-Hawaii-Aleutian Daylight Time (UTC -9) and SDT-Samoa Daylight Time (UTC -10).

Physiography
The total area of the US 3,796,742 sq mi (9,826,67 sq km), making it the third largest country in the world. The land area is 3,531,905 sq mi (9,147,590 sq km) while the remaining 264,837 sq miles (685,930 sq km) is covered by water.

The vast geographical extent of the country has many distinct landforms. Extensive plains cover most of the central part and are called the Great Plains. These plains are bound by the high Rocky Mountains in the west and low mountains and hills of the Appalachian Range in the east. Alaska is characterized by rugged mountains and broad river valleys while the islands of Hawaii have volcanic topography. The coastal areas of the country comprise beaches, bays, deltas, marshes, mudflats, and swamps.


The highest point in the country is Mount McKinley (Denali) in Alaska, which is 20,310 feet (6,194 m) high. The lowest point is the Death Valley in California which lies at -279 feet (-85 m) below sea level. The highest point in the contiguous 48 states is Mt. Whitney, California, at 14,508. Interestingly, Mt. Whitney, the highest point, and Badwater Basin in Death Valley, the lowest point, are only 132 miles apart.

Climate
The US has a large latitudinal extent, because of this, the temperature varies considerably across the country from north to south. The annual mean temperature ranges from as low as 27 degrees f (-3 degrees c) at Fairbanks, Alaska, to about 52 degrees f (11 degrees c) in Seattle, WA in the Pacific Northwest.

Rainfall in the country reduces from the west to east, i.e., from the Rockies across the Great Plains. However, the central ‘Great Plains’ or the Mid-West, is a meeting ground for cold northerly winds from the Arctic and the humid southerly winds from the Gulf of Mexico, making it a tornado-prone zone, especially in spring. This area is often referred to as ‘Tornado Alley.’ The high rainfall areas of the country are the south-eastern region (Miami 55 inch) and the Pacific Northwest coastal belt (Seattle 37 inch). In late summer and early autumn, high temperatures in the Caribbean and the Gulf of Mexico trigger hurricanes, which bring heavy rain to the Gulf States, and sometimes to the entire eastern seaboard.

In general terms, there are four seasons in the U.S - Spring (April to June), Summer (July to September), Fall (October to December), and Winter (January to March).


Hydrology
The Continental U.S is crisscrossed by over 800 rivers. The major rivers of the country are the Colorado, Columbia, Mississippi, Missouri, Ohio, Rio Grande, Sacramento, San Joaquin, Snake River, and the Yellowstone. The Mississippi-Missouri river system is the longest in the country and drains more than half of the U.S.A.

Of the five great lakes, Lake Superior, Huron, Erie, and Ontario are shared by the U.S.A. and Canada and only Michigan lies entirely in the U.S.A. Amongst the other largest lakes in the country are the Great Salt Lake in Utah, Lake Okeechobee in Florida, and Lake Iliamna in Alaska.


Environmental Geography
Biodiversity In the US, more than 200,000 species of life forms are known to have been formally studied and named. But it is believed that this number may not even be half of the total plants, animals, and microbes found in the country. The US is considered to have a more diverse ecosystem than any other nation in the world and is particularly rich in aquatic life.

Iconic flora of the US includes the Prairie grass of the Prairies, the Giant Redwood of California, and the Giant Saguaro cacti found in the US deserts. The fauna would include the Grizzly bear, bison, wolf, prairie dog, rattlesnake, and alligator.

National Parks
The US has 60 National Parks spread over most of the 50 states. Some of the most visited national parks in the country are the Great Smoky Mountains in North Carolina and Tennessee; the Grand Canyon in Arizona; Yosemite in California; Yellowstone in Idaho, Montana and Wyoming; Olympic in Washington; Rocky Mountain in Colorado; Grand Teton in Wyoming; Zion in Utah; Cuyahoga Valley in Ohio, and Glacier in Montana.