North America.

The USA is divided into six time zones:
Eastern Standard Time: GMT - 5 (GMT - 4 from second Sunday in March to first Sunday in November).
Central Standard Time: GMT - 6 (GMT - 5 from second Sunday in March to first Sunday in November).
Mountain Standard Time: GMT - 7 (GMT - 6 from second Sunday in March to first Sunday in November. Arizona does not observe DST).
Pacific Standard Time: GMT - 8 (GMT - 7 from second Sunday in March to first Sunday in November).
Alaska: GMT - 9 (GMT - 8 from second Sunday in March to first Sunday in November).
Hawaii: GMT - 10.

9,826,630 sq km (3,794,083 sq miles).

301 million (official estimate 2007).

32.5 per sq km.

Washington, DC. Population: 581,530 (2006). Over 25 other cities have a population larger than that of Washington, DC. New York is the largest city, with a population of 8.3 million (2006). Chicago, Dallas, Houston, Los Angeles, Philadelphia, Phoenix, San Antonio and San Diego had populations ranging from 1.2 - 3.8 million in 2005.

Covering a large part of the North American continent, the USA shares borders with Canada to the north and Mexico to the south and has coasts on the Atlantic, Pacific and Arctic oceans, the Caribbean Sea and the Gulf of Mexico. The State of Alaska, in the northwest corner of the continent, is separated from the rest of the USA by Canada, and Hawaii lies in the central Pacific Ocean. The third-largest country in the world (after the Russian Federation and Canada), the USA has an enormous diversity of geographical features. The climate ranges from subtropical to Arctic, with a corresponding breadth of flora and fauna. For a more detailed description of each region's geographical characteristics, see the individual state sections.

Federal Republic since 1789. Gained independence from the UK in 1776. The USA has 50 States and the District of Columbia (as in ‘Washington, DC'), which lies between Maryland and Virginia.

President Barack Obama since 2009.

National security in general is a major issue for the USA. President George W Bush secured a second term at the presidential election in November 2004 while the Republicans tightened their grip on the Senate, kept control of the House of Representatives, and also presided over the possibility of further changes in the Supreme Court. Mid-term election results in November 2006 represented a turnaround of public opinion as the Democrats gained the majority in the Senate and House of Representatives.

The election of November 2008 saw a record turnout and victory to Democrat candidate Barack Obama. He took over from George W Bush as president in January 2009.

English, with significant Spanish-speaking minorties (10.7%).

Protestant majority (52%) with Roman Catholic, Mormon, Jewish and many ethnic minorities.

110 volts AC, 60Hz. Plugs are of the flat two-pin type. European electrical appliances not fitted with dual-voltage capabilities will require a plug adaptor, which is best purchased before arrival in the USA.

Americans are renowned for their openness and friendliness to visitors. The wide variety of national origins and the USA's relatively short history has resulted in numerous cultural and traditional customs living alongside each other. In large cities, people of the same ethnic background often live within defined communities. Shaking hands is the usual form of greeting. A relaxed and informal atmosphere is usually the norm. As long as the fundamental rules of courtesy are observed, there need be no fear of offending anyone of any background. Gifts are appreciated if one is invited to a private home. As a rule, dress is casual. High-end restaurants, hotels and clubs may require more formal attire. Smoking is increasingly unpopular in the US; it is essential to ask permission before lighting up. Smoking is not allowed on city transport and restricted or forbidden in public buildings in most states. There will be a posted notice where no smoking is requested. An increasing number of states (including California and New York) have banned smoking altogether in bars, restaurants and many public places.

Information on the USA is provided in two parts: a general overview and individual State profiles, each of which has its own section.