
The United States of America is a federal constitutional republic comprising fifty states and a federal district. The country is situated almost entirely in the western hemisphere: its forty-eight contiguous states and Washington, D.C., the capital district, lie in central North America between the Pacific and Atlantic Oceans, bordered by Canada to the north and Mexico to the south; the state of Alaska is in the northwest of the continent with Canada to its east, and the state of Hawaii is in the mid-Pacific. The United States also possesses fourteen territories, or insular areas, that are scattered around the Caribbean and Pacific.
At 3.79 million square miles (9.83 million km²) and with over 300 million people, the United States is the third or fourth largest country by total area, and third largest by land area and by population. The United States is one of the world's most ethnically diverse nations, the product of large-scale immigration from many countries. Its national economy is the largest in the world, with a nominal 2006 gross domestic product (GDP) of more than US$13 trillion.
The nation was founded by the thirteen colonies of Great Britain located along the Atlantic seaboard. After proclaiming themselves as "states," they issued the Declaration of Independence on July 4, 1776. The rebellious states defeated Britain in the American Revolutionary War, the first successful colonial war of independence.
A federal convention adopted the current United States Constitution on September 17, 1787; its ratification the following year made the states part of a single republic. The Bill of Rights, comprising ten constitutional amendments, was ratified in 1791. In the nineteenth century, the United States acquired land from France, Spain, Mexico, and Russia, and annexed the Republic of Texas and the Republic of Hawaii. The American Civil War ended slavery in the United States and prevented a permanent split of the country. The Spanish-American War and World War I confirmed its status as a military power. In 1945, the United States emerged from World War II as the first country with nuclear weapons and a permanent member of the United Nations Security Council. The sole remaining superpower in the post–Cold War era, the United States is perceived by many as the dominant economic, political, cultural, and military force in the world
The Commonwealth of Massachusetts (IPA: /ˌmæsəˈtʃuːsɨts/) is a state in the New England region of the northeastern United States. Most of its population of 6.4 million live in the Boston metropolitan area. The eastern half of this relatively small state is mostly urban and suburban. The west is primarily rural, also with most of its population in urban enclaves. Massachusetts is the most populous of the six New England states and ranks third in overall population density among the 50 states.
Massachusetts has been a significant state in American history. Plymouth, Massachusetts was the second permanent English settlement in North America. Colonists from England founded many towns and villages in the present-day territory of Massachusetts very early in the nation's history - in the 1620s and 1630s. The Boston area became known as the "Cradle of Liberty" for the ferment there which led to the American Revolution and the independence of the United States from Great Britain. Massachusetts was the first U.S. state to abolish slavery, and was a center of the temperance movement and abolitionist activity in the years leading to the American Civil War. The state has contributed many prominent politicians to national service, including the Kennedy family.
Originally dependent on agriculture and trade with Europe, Massachusetts was transformed into a manufacturing center during the Industrial Revolution. Migration of factories to the lower-wage southern states caused economic stagnation during the first half of the 20th Century. The Massachusetts economy was revived after World War II, and today is prominent in higher education, health care, and high technology.
Massachusetts is bordered on the north by New Hampshire and Vermont; on the west by New York; on the south by Connecticut and Rhode Island; and on the east by the Atlantic Ocean. Most of the state is uplands of resistant metamorphic rock that were scraped by Pleistocene glaciers that deposited moraines and outwash on a large, sandy, arm-shaped peninsula called Cape Cod and the islands Martha's Vineyard and Nantucket to the south of Cape Cod. Upland elevations increase to the north and west and the highest point in the state is Mount Greylock at 3,491 feet (1,064 m) near the state's northwest corner.
The uplands are interrupted by the downfaulted Pioneer Valley along the Connecticut River and further west by the Housatonic Valley separating the Berkshire Hills from the Taconic Range along the western border with New York.
Boston is located at the innermost point of Massachusetts Bay, at the mouth of the Charles River, the longest river entirely within Massachusetts. Most of the population of the Boston metropolitan area (approximately 4.4 million) does not live in the city proper; eastern Massachusetts on the whole is fairly densely populated and largely suburban as far west as Worcester.