American Brief HistoryBefore Colonial periodForty thousand years ago, a group of Rangers from Asia through North America to Central and South America, these people are the ancestors of the Indians. Indians living in the Americas when Columbus reached the New World ,There are about 30 million, of which about 20 million people live in Canada and the United States, north-central, the rest of the vast majority live in Mexico and the United States south. About 10,000 years ago, there are another group of Asians migrated to northern North America, which is later Eskimos. The earliest American Caucasian may be Vikings, they are a group of adventurous fishing, some people think that 1,000 years ago, they have been to the east coast of North America.Colonial periodIn 1607, one of about 100 people of colonial groups in Chesapeake Beach Jamestown, which is the first permanent colony built by the British in North America, after 150 years, one after another coming Many colonists settled in the coastal areas, many of them from the United Kingdom, and also in part from France, Germany, the Netherlands, Ireland and other countries. The mid-18th century, the 13 British colonies gradually formed, they have their own government and Parliament in the highest British sovereignty. The 13 colonial area due to the differences of climate and geographical environment, resulting in economic patterns around, the difference between the political system and the concept.Independence MovementThe mid-18th century, the British colonies in the Americas and the United Kingdom, the existing cracks. With the continuous expansion of the colony, and gradually make them aware of the seriousness of the developments, which sprouted the idea of an independent.In 1773, the Boston Tea Party, anti-British colonists dumping.In 1774, representatives from 13 states gathered in Philadelphia, convened the First Continental Congress, hoping to solve the problem peacefully and the United Kingdom. King, however, adhere to the colony must unconditionally surrender to the British king, and accept the punishment. 1775, in Massachusetts, to Lexington flames of war, the outbreak of the War of Independence in North America.Held in Philadelphia in May 1776, the Second Continental Congress, staunch war with the independent determination, and published his famous Declaration of Independence, put forward a good reason to fight the battle. Issued the Declaration of Independence is considered to be the beginning of the establishment by the United States, this day (July 4) was also the United States as a National Day.In October 1777, Saratoga victory, reversing the negative trend of the war of independence early. The campaign to make the American peoples confidence, and international support.France and the United States signed a military alliance treaty in February 1778, France officially recognized the United States. France, Spain, the Netherlands have war.In 1781, the Battle of Yorktown Victory, the U.S. military has won a decisive victory. Yorktown after the battle, in addition to the sea there are several warring and sporadic fighting on land, the war of the North American continent has basically stopped.The success of the revolution, the American people have the opportunity to express their political ideas in legislative form. Federal Assembly 1787, held in Philadelphia, in Washington pushed for President, they take a matter of principle, that the central authority is a general, but there must be prudent regulations and instructions, at the same time, they also accept the fact that national government must tax, coin money, to adjust the commercial, a declaration of war and the power to enter into treaties. In addition, in order to prevent the central authority is too large, and to take the politics Montesquieu doctrine, that the Government set three equal cooperation with the department, that the three powers of the legislative, executive, and judicial checks and balances to reconcile checks and balances, rather than make any rights accounted for controlling position.In 1812, Britain again invaded the newly established United States, known as the Second War of Independence, the post-war U.S. states more united.Westward expansionThe early 19th century, thousands of people across the Appalachian Mountains, moved west. Some pioneers, emigrated to the United States border, belong to the territory of Latin America north of Mexico, between Alaska and California, Oregon and even depth.In 1846, the outbreak of the Mexican-American War, the United States expanded their area.Civil WarThe cause of the Civil War, not only economic, political, military and ideological conflict. The civil war has exposed the weakness of the United States. The existence of this country, and made some test. After the test, the United States was moving towards the royal road to a centralized modern state. Slavery issue between the North and the South would