Public health officials are pleading with Americans to avoid large crowds and hold more muted Independence Day celebrations, while President Donald Trump promised a "special evening" in Washington that could bring tens of thousands to the National Mall.
The United States has seen a spike in its Covid-19 outbreak, with a record rise in the number of daily coronavirus cases recorded.
Mr Trump's Salute for America celebration on Saturday evening includes a speech from the White House South Lawn that he said would celebrate American heritage.
The president also plans for a military flyover and an enormous fireworks display that could see people pack into the city centre.
The president kicked off the holiday weekend by travelling to Mount Rushmore in South Dakota for a fireworks display on Friday night near the mountain carvings of George Washington, Thomas Jefferson, Abraham Lincoln and Theodore Roosevelt.
In his remarks, Mr Trump accused protesters - who have pushed for racial justice in the wake of the killing of George Floyd - of engaging in a "merciless campaign to wipe out our history".
In a presidential message on Saturday - the 244th anniversary of the adoption of the Declaration of Independence - Mr Trump said: "Over the past months, the American spirit has undoubtedly been tested by many challenges".
His Democratic rival, Joe Biden, said in a statement that the US "never lived up" to its founding principle that "all men are created equal".
He added: "We have a chance to rip the roots of systemic racism out of this country".
Mr Trump's participation in big gatherings comes as many communities have decided to scrap fireworks, parades and other holiday traditions.
The goal is to try to prevent further spread of coronavirus, which large gatherings could spur.
Confirmed cases are climbing in 40 states - the US set another record on Friday with 52,300 newly reported infections, according to the tally kept by Johns Hopkins University.
For the Mount Rushmore event, Republican governor Kristi Noem, a Trump ally, insisted social distancing was not necessary and masks were optional.
Mr Trump recently appeared to change his opinion on face masks - having rarely appeared in public wearing one.
Mr Trump spent little time in his Mount Rushmore address reflecting on the pandemic, which has killed more than 129,000 Americans.
The Centres for Disease Control and Prevention (CDC) cautions that mass gatherings such as the one scheduled for Washington present a high risk for spread of the virus.
Interior officials said they would hand out 300,000 face coverings to spectators who gather on the National Mall.
Interior department secretary David Bernhardt said visitors would be encouraged to wear masks and keep a 6ft distance from one another.
There was no indication that would be mandatory, despite the recommendations of health officials.
Washington mayor Muriel Bowser, who said she did not have the right to shut down the holiday spectacle because it is on federal land, warned the federal government about the obvious dangers of such a large crowd.
On Friday, she urged the city’s residents to be smart about how they spend the holiday.
"Just because someone invites you to a party doesn't mean you have to go," Ms Bowser tweeted.