The United States of America is the third largest country in the world, and the largest English-speaking nation. It is located in North America, bordered by Canada to the North, the Atlantic Ocean to the East, Mexico to the South, and the Pacific Ocean to the West. It has two additional states not connected to the main continent (referred to as the continental United States); Hawaii, a chain of islands in the Pacific Ocean, and Alaska, a large state connected to Northwestern Canada. The United States also has 14 dependent islands in the Pacific and Atlantic Oceans; they don't have the same rights and privileges as states, but are still considered US territories.
The United States is the fourth most populous country on the planet. The majority of Americans live along the four edges: the East Coast, the West Coast, the Eastern Canadian border, and the Mexican border. The rest of the population is spread out throughout the South and East, with the central-North regions be less populated. The people in Hawaii live mostly on one island, Oahu. The majority of Alaskans live along the Southern coast of the state, especially in the city of Anchorage.
The United States has a long history of native populations, dating back thousands of years. It is thought that a few decades before Europeans discovered the US, a widespread plague spread throughout the native populations of the land and wiped out a huge portion of them. When European settlers did come to discover the land, they began long history of oppression and assimilation, which has led to a number of issues with people of native descent today, most notably economic issues.
The United States' states were owned by a number of European nations, most notably France and Great Britain, with some states being owned by Mexico. The United States became independent from Great Britain on July 4th, 1776, when it was formed with 13 states. Over time, it kept gaining states from the other nations, sometimes through war (as with Mexican-owned Texas), and other times simply by purchasing the land (as with buying Alaska from Russia). The US now consists of 50 states.
The flag, referred to as Old Glory, has 50 white stars for each of its 50 states, and the 13 red and white stripes represent the 13 original colonies that made up the nation. The blue stands for loyalty, justice, truth, and friendship. Red stands for courage, zeal, and fervency (intensity). White stands for purity and rectitude (morality) of conduct.
The "United States" refers to the fact that 13 colonies united to form a new country, and referred to themselves as states from that point on. "America" refers to an Italian explorer, Amerigo Vespucci, from the 15th century.