The main event falls on Saturday – Independence Day – with festivities running for months beforehand.
They are being led by Freedom 250, an organisation Trump announced last year.
This is separate from America 250, a bipartisan body Congress set up and funded a decade ago to plan the anniversary.
For Saturday evening, Trump has promised a "spectacular rally" in Washington, followed by what he says will be the biggest fireworks display in history.
In June, a mixed martial arts event was held in the White House gardens, on a purpose-built arena.
It coincided with Flag Day and Trump's 80th birthday, but was also billed as part of the anniversary events.
Last week, an exhibition celebrating US states opened in central Washington, though it has not drawn large crowds.
Trump's image will appear on limited-edition passports, which Americans can apply for from 6 July while stocks last.
In March, officials approved putting his portrait on a commemorative 24-carat gold coin, and his signature is set to appear on new banknotes.
A triumphal arch is planned too – 76 metres tall, topped with a gold Statue of Liberty guarded by four gold lions.
Trump has suggested the new ballroom being built at the White House is also linked to the anniversary.
The plans have drawn criticism.
Much of the US media argues Trump is turning the independence celebrations into a personal, political showcase.
The Washington Post said his habit of putting his own name on projects has now extended to the 250th anniversary.
Many historians and politicians fear that what could have been a unifying moment for a divided country is instead becoming so closely tied to Trump that it risks deepening political divisions further, the paper wrote.
In August, further anniversary events are planned in Washington, including IndyCar races and the "Patriot Games", featuring the top two high school athletes from every US state.
(ał)
Source: PAP