Rival rallies have been staged in Washington DC as conservatives and civil rights leaders sparred over the legacy of Martin Luther King.
A rally on Saturday at the Lincoln Memorial was organised by talk show host Glenn Beck at the spot where Martin Luther King gave his famous I have a Dream speech.
Black Americans have criticised the rally, saying the organisers are trying to hijack celebrations to remember Dr King.
Mr Beck, a presenter for Fox News, insisted the timing was a coincidence.
He said he was unaware when he was planning the rally that Saturday, 28 August, would be the anniversary of the 1963 march.
The BBC reports a counter-rally was held elsewhere by civil rights campaigner Rev Al Sharpton.
Former US vice-presidential candidate Sarah Palin also spoke at the Lincoln Memorial.
She compared the crowd with the civil rights activists who marched on Washington in 1963 to hear Dr King's speech and said they had the same moral courage as George Washington, Abraham Lincoln and Dr King.
We must restore America and restore her honour, she said.
Much of the rally was devoted to paying tribute to the US military, including wounded veterans of wars in Iraq and Afghanistan.
Addressing the crowd, Mr Beck said the US had wandered in darkness for too long.
America today begins to turn back to God, he said.
He told the crowd the timing of the Restoring Honour rally was coincidence, but also divine providence.
The BBC reports Mr Beck is a prominent voice in the Tea Party movement which has galvanised conservatives opposed to taxes and government intervention.
Singer Marian Anderson performed at the Lincoln Memorial on Easter Sunder 1939 after she was not allowed to perform in Constitution Hall, where only white artists were welcome. Her concert was opened by Eleanor Roosevelt.