In the United States, Independence Day (commonly known as "the Fourth of July" or "July 4th") is a federal holiday celebrating the adoption of the Declaration of Independence on July 4, 1776, declaring independence from Great Britain.

Independence Day is commonly associated with fireworks, parades, barbecues, beer, picnics, baseball games, and various other public and private events celebrating the history, government, and traditions of the United States. Fireworks have been associated with the Fourth of July since 1777.

-From Wikipedia:  http://en.wikipedia.org/wiki/4th_of_july