From the U.S. Census

By the numbers: Our population

On this day 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.

2.5 million
In July 1776, the estimated number of people living in the newly independent nation.

310 million
The nation's estimated population on this July Fourth.

Sources: U.S. Census 2010; Population clock ; Historical Statistics of the United States: Colonial Times to 1970