About This Region
The United States of America, commonly referred to as the United States, is a federal constitutional republic composed of the District of Columbia, 50 states, and numerous overseas territories such as Guam. Its main body is located in the central part of North America. According to the initial editions of the CIA World Factbook from 1989 to 1996, the total area of the United States was 9,372,610 km², which was revised in 1997 to 9.63 million square kilometers (including the U.S. sovereign portion of the Great Lakes and the areas of estuaries, harbors, inland seas, and other coastal waters), with a population of 320 million. English is the common language, and it is a nation of immigrants. Many of the world's major ports are also located in the United States; the busiest are the Port of Los Angeles and the Port of Long Beach in California, as well as the Port of New York, all of which are among the busiest ports in the world. The Great Lakes region (Lake Superior, Lake Michigan, Lake Erie, Lake Huron, and Lake Ontario) also has extensive shipping traffic, with each of the Great Lakes extensively connected to the Mississippi River network, and the lowest reaches of the river leading directly to the Atlantic Ocean. The Erie Canal, the first to connect the Great Lakes with the Atlantic Ocean, facilitated the rapid agricultural and industrial development of the American Midwest and made New York City the economic center of the United States. The main export commodities of the United States are: chemical products, machinery, automobiles, aircraft, electronic information equipment, weapons, food, pharmaceuticals, beverages, etc. The main import commodities are: food, clothing, electronic equipment, machinery, steel, textiles, petroleum, natural rubber, and metals such as tin and chromium.