Tens of millions of small-town Americans and city dwellers alike will line parade routes, watch fireworks, attend picnics, concerts and family gatherings. In Washington, hundreds of thousands of spectators will pack the National Mall for a nationally televised concert and a massive display of fireworks.

President Obama joins the USO to host the White House's fourth annual salute to the military, with a barbecue, games and a concert by the presidential Marine Band. Additionally, Mr. Obama's daughter Malia turns 14 on Wednesday, but it is not known whether she will celebrate at these festivities.

Fireworks also will light the night skies over hallowed battlefields from the War of 1812 and America's 19th century Civil War.  Similar festivities are slated for Philadelphia (the nation's first capital), Annapolis, Maryland and New York City.

Drafted by Thomas Jefferson in June 1776, the Declaration of Independence is America's most cherished symbol of freedom.  The Continental Congress formally approved the document weeks later on July 4.

Many localities in the western state of Colorado have banned fireworks displays this year, after weeks of dry weather and massive wildfires.  A number of other displays have been canceled, after triple-digit temperatures spawned summer storms that ravaged wide swaths of the Midwest and Mid-Atlantic regions late last week.