The state visit, by far the most high-profile and consequential of Charles' reign, marks the 250th anniversary of the US Declaration of Independence from British rule, and is the first to the country by a British monarch in two decades.
Charles and Camilla touched down at Joint Base Andrews where they were greeted by diplomatic, state and federal officials as well as senior members of the British embassy and accepted flowers from the children of British military families stationed in the United States.
They proceeded to the White House, where they were greeted by Trump and first lady Melania Trump, who exchanged kisses on the cheek with the King and Queen while the president shook their hands. The four stood briefly for photographers before retreating inside for a private tea.
The week's schedule also includes a Tuesday address to Congress, a lavish state dinner at the White House and a Wednesday stop in New York City. The Washington events take place with much of the US capital still on edge following the White House Correspondents' Association dinner shooting on Saturday.
While Trump is an unabashed fan of the British royal family who regularly describes Charles as a "great man," he has had differences with the British government of Prime Minister Keir Starmer. Starmer is hoping the visit will shore up the future of the two allies' "special relationship," which is at its lowest point since the Suez Crisis in 1956.
The long-planned visit has become enmeshed in a political spat between the two countries over the US-Israeli war on Iran, which led Trump to voice deep displeasure with the British government for failing to support the offensive.
The 77-year-old king, who is still undergoing treatment for cancer, on Tuesday will become the second British monarch to address the US Congress.
The royals will then head to New York City where they will commemorate those killed in the September 11, 2001, attacks ahead of the 25th anniversary, while the queen will also mark the centenary of children's stories featuring Winnie the Pooh.
The trip concludes in Virginia with the King meeting those involved in conservation work, a nod to his half-century of environmental campaigning.
Britain's ambassador to the US, Christian Turner, said the visit would underscore the shared history, sacrifice and common values between the two countries, adding that the approach would be a very British one: "Keep calm, carry on."
While Trump has in recent days eased his criticism of Britain over its response to the Iran war, an internal Pentagon email set out how the US could review its position on the UK's claim to the Falkland Islands as punishment for its lack of support, further straining ties.
One issue Charles will try to avoid during his visit is the Jeffrey Epstein scandal.
Royal sources have said it was not possible for the royal couple to meet any victims of Epstein during the tour, as some have requested, to avoid impacting any potential criminal cases. Charles' brother, Andrew Mountbatten-Windsor, whose reputation and royal standing have been destroyed by his links to the late US sex offender, is facing police inquiries over his connections. The former Prince Andrew has denied any wrongdoing.
with PA
