On this day (July 4) in 1776, the Declaration of Independence was approved by the Continental Congress, setting the 13 colonies on the road to freedom as a sovereign nation. As always, this most American of holidays will be marked by parades, fireworks and backyard barbecues across the country this year, too. 

2,500,000 was the estimated number of people living in the newly independent nation in July of 1776. In 2011, that number will exceed 311,400,000. In fact, this information is from the United States Census Bureau and you can keep track of the US population at the U.S. & World Population Clocks.