A few dozen people still remain outside - a significant number have been stationed here for the majority of the day.
Among them is a mixture of Trump supporters wearing red 'Make America Great Again' hats, demonstrators carrying placards, and passers-by hoping to catch a glimpse of the US president.
There's also a sea of journalists and cameras lined up along the side of the road.
But they won't see much. Trump isn't scheduled to come out here, and there aren't any more planned events that will be visible from outside the castle walls.Next up on the schedule is a state banquet later this evening, which is taking place inside the castle.
It's been a busy day for both King Charles III and President Trump - but it's not quite over yet:
First up: The King will be hosting a state banquet this evening in St George's Hall, at Windsor Castle, to honour the US president's visit - both are expected to deliver short speeches ahead of dinner.
And then: President Trump and First Lady Melania will then overnight at Windsor Castle.
Thursday morning: Trump will leave the Berkshire royal residence to meet Prime Minister Keir Starmer at his country residence, Chequers.
At the same time... Melania Trump will remain in Windsor to accompany the Queen on a visit to Queen Mary’s Dolls’ House and the Royal Library
The first lady will then join the Princess of Wales to meet Chief Scout Dwayne Fields at Frogmore Gardens before travelling to Chequers to be reunited with the president.
Meanwhile, the scene back in central London paints a different one from the images we've just seen in Windsor.
The Stop Trump coalition protest, numbering a few thousand, paused outside Downing Street which was being protected by officers from Wales and Northern Ireland.
They've now made their way to Parliament Square, where the first performer on the stage was Billy Bragg.People take part in a 'Trump Not Welcome' protest during the state visit of U.S. President Donald Trump and first lady Melania Trump, as
A short while ago, a convoy of black American vehicles left Windsor Castle along the high street.Some people here were hoping President Trump might have been inside one of the cars - but there’s no plans for him to come out here.
A few began chants of “USA”, others shouted “we love Trump”. Crowd takes pictures as black US vehicles drive past
he Prince and Princess of Wales receive US President Donald Trump and First Lady Melania Trump at Windsor Castle in Windsor, Berkshire, on day one of their second state visi
The Trumps were greeted by the Prince and Princess of Wales earlier at Windsor Castle
The Prince and Princess of Wales had their own short private meeting with President Trump and Melania during the day.
It was said afterwards to have been a warm and friendly encounter, with Prince William and Catherine an important part of the royal welcome.
Trump has been an enthusiastic fan of Prince William, having spoken highly of their "great, great talk" when they met in France last year.
Melania and Catherine will be attending an event together on Thursday, which is likely to draw attention.
King Charles (L) shakes hands with a young girl with blonde hair in a low plait while Donald Trump (R) watches as a member of the British Air Force salutes
The King and Queen are now leaving the ceremony - with Donald Trump and Melania walking beside them.They could be seen shaking hands with military personnel as they left the East Lawn of Windsor Castle.
Red Arrows flypast over Windsor Castle seen from the road outside .Outside Windsor Castle cameras were raised to the skies in anticipation for the Red Arrows flypast.
Right on cue you could hear the planes roar as a stream of red, white and blue flashed across the skies.It was followed by some small cheers and applause from the gathered crowd.
Many people here appear to have turned up just to see the flypast - with crowds increasing over the past ten minutes or so. A child nearby was counting down how long it would be.