Clinton was in New York for an appearance before home-state supporters. Officials said she would concede Obama had the delegates to secure the Democratic nomination, effectively ending her bid to be the nation's first female president.
McCain, who wrapped up the Republican nomination months ago, campaigned in Memphis.
Obama sealed his nomination based on primary elections, state Democratic caucuses and delegates' public declarations as well as support from 22 delegates and "superdelegates" who privately confirmed their intentions to The Associated Press. It takes 2,118 delegates to clinch the nomination at the convention in Denver this summer.
The young senator's success amounted to a victory of hope over experience, earned across an enervating 56 primaries and caucuses that tested the political skills and human endurance of all involved.
Obama stood for hope, and change. Clinton was the candidate of experience, ready, she said, to serve in the Oval Office from Day One.
Together, they drew record turnouts in primary after primary – more than 34 million voters in all, independents and Republicans as well as Democrats.
Yet the race between a black man and a woman exposed deep racial and gender divisions within the party.
Obama drew strength from blacks, and from the younger, more liberal and wealthier voters in many states. Clinton was preferred by older, more downscale voters, and women, of course.
Obama's triumph was fashioned on prodigious fundraising, meticulous organizing and his theme of change aimed at an electorate opposed to the Iraq war and worried about the economy – all harnessed to his own gifts as an inspirational speaker.
