The United States has the largest and richest economy in the world, with a gross domestic product exceeding $18.5 trillion and GDP per capita exceeding $54,000. It is the third-largest country in terms of both geographic area and population. Its 320 million residents primarily speak English with 60 million speaking a language other than English at home. English is the language used in nearly all government functions. The federal government, each of the fifty states, and many cities, counties, and other local jurisdictions have independent legal systems that overlap. All federal and state legal systems are based on English common law with the exception of Louisiana. The United States also participates in many international agreements and organizations.
The U.S. economy has generally been marked by steady growth, low unemployment and inflation, and rapid advances in technology. The United States has a market economy where individuals and businesses make most decisions, and federal and state governments buy goods and services predominantly from the private sector. Businesses enjoy considerable flexibility in decisions regarding investment, employment, and strategy. The economy is diverse, and the United States is self-sufficient in rawest materials. Its labour force is the third-largest labour force in the world and encompasses all ages, races, and genders. The U.S. dollar is not subject to exchange control. Interest rates of the central bank have been kept at historically low rates since 2008.
The United States possesses an extensive network of ports, railroads, airports and an interstate highway system linking all commercial centres for the movement of people and cargo. For the business traveller, numerous major cities have international airports. Flights within the United States are usually relatively inexpensive and convenient. Business travellers typically do not utilize rail travel between cities except for the Washington, D.C.-New York-Boston corridor. Ground transportation options at airports vary considerably for the business traveller. For personal transportation within a metropolitan area, the quality and convenience of mass transit varies depending on the city; in many cases, a rental car, taxi, or licensed car service may be the best option for the business traveller.