Barack Obama was elected the nation's first black president Tuesday night in a historic triumph that overcame racial barriers as old as America itself. 

The 47-year-old Democratic senator from Illinois sealed his victory by defeating Republican Sen. John McCain in a string of wins in hard-fought battleground states - Ohio, Florida, Virginia and Iowa. 

A huge crowd thronged Grant Park in Chicago to cheer Obama's improbable triumph and await his first public speech as president-elect.

Obama and his running mate, Sen. Joseph Biden of Delaware, will take their oaths of office as president and vice president on Jan. 20, 2009. 

As the 44th president, Obama will move into the Oval Office as leader of a country that is almost certainly in recession, and fighting two long wars, one in Iraq, the other in Afghanistan.