(CNN) - Barack Obama told supporters that "change has come to America," as he addressed the country for the first time as the president-elect.
"The road ahead will be long. Our climb will be steep. We may not get there in one year or even one term, but America - I have never been more hopeful than I am tonight that we will get there. I promise you - we as a people will get there," Obama said in Chicago, Illinois.
Watch: Obama calls on Americans
Police estimated that 125,000 people gathered in Grant Park to hear Obama claim victory.
Obama said he was looking forward to working with Sen. John McCain and Gov. Sarah Palin "to renew this nation's promise in the months ahead."
McCain on Tuesday urged all Americans to join him in congratulating Sen. Barack Obama on his projected victory in the presidential election.
Watch: Jesse Jackson breaks down
"I pledge to him tonight to do all in my power to help him lead us through the many challenges we face," McCain said before his supporters in Phoenix, Arizona.
"Today, I was a candidate for the highest office in the country I love so much, and tonight, I remain her servant," he said.
McCain called Obama to congratulate him, Obama's campaign said.