The bulk of the activity will take place in London, where people plan to gather first in Regent's Park outside of the US ambassador's house on Thursday and again across central London for a series of protests throughout the day on Friday.
The largest demonstration is expected in central London on Friday where a giant "Trump baby" balloon will fly close to Parliament after being given the go-ahead by London mayor Sadiq Khan.
Organizers of anti-Trump rallies say they are not expecting any trouble at all - and that it would be very unlikely for any hostility to be directed at ordinary Americans.More news: Bucks Rookie Donte DiVincenzo Reveals He's Basically Broke After Leaving Villanova
In the Tuesday memo, the U.S. Embassy in London alerted citizens to the "numerous demonstrations" that could "attract large crowds" that may be less than agreeable toward Americans.
Most of the protests will take place that day in central London, the US officials said, with some occurring the days before and after.
Mr Mundell said he is looking forward to welcoming the president.
British law requires any petition supported by more than 100,000 people to be considered for parliamentary debate, even though there was no serious attempt to prohibit Mr. Trump from coming to Britain. It was an extraordinary rebuke from a close ally.
In a statement ahead of Trump's arrival, she said the visit would focus on trade and strengthening defense and security ties, saying there was no stronger alliance than Britain's "special relationship with the U.S".More news: Liverpool Eye Swoop For International Star As Klopp Lines-Up 3rd Signing
In Brussels, Mr Trump and Prime Minister Theresa May had the chance to speak to each other ahead of his visit.
The couple will attend a gala dinner at Blenheim Palace out in the countryside on Thursday evening.
The Trump Baby Blimp is inflated during a practice test, at Bingfield Park in north London.
The two leaders will hold talks the following day at Chequers, the 16th-century manor house which is the prime minister's official country residence which will focus on Russian Federation, trade, Brexit and Middle East.
Later, Trump will go to Windsor Castle for tea with the 92-year-old queen. Separately, his wife, Melania, will visit war veterans and schoolchildren in a London visit accompanied by Philip May, the prime minister's husband.More news: Trump rails against Germany, demands allies double North Atlantic Treaty Organisation spending