Queen Elizabeth II and Prince Philip landed on America’s shores in February 1983 after sailing the Royal Yacht Britannia, which docked at San Diego’s Broadway Pier, across the Atlantic Ocean.
Although she had thought that an official visit to a US president should take place in Washington, then-president Ronald Reagan convinced the queen to go to his home state of California.
The official 10-day tour began with tunes of God Save the Queen, the US national anthem and the roaring cheers of about 3,000 well-wishers.
Before heading north to Los Angeles, the queen and prince visited the world-famous San Diego Zoo, the USS Ranger aircraft carrier and the Old Globe theatre in Bilbao Park.
She then travelled to Los Angeles for a star-studded gala at 20th Century Fox studios, where the M*A*S*H sound stage was transformed into a venue fit for a queen.
Hosted by first lady Nancy Reagan, notable performers who attended included Michael Caine, Elton John, Fred Astaire, Jimmy Stewart, Bette Davis, Ginger Rogers, Loretta Young, Irene Dunne, June Allyson and Zsa Zsa Gabor.
Frank Sinatra, Perry Como, Dionne Warwick and George Burns performed at the gala, while Ed McMahon acted as the evening’s master of ceremonies.
Two days later, the queen was greeted in Los Angeles by the city’s mayor, Tom Bradley.
In a speech at City Hall, she defended Britain’s actions in the Falkland Islands and praised Los Angeles’ diversity and economy.
She even made a joke comparing her northward journey from San Diego to a trip made 400 years ago by Sir Francis Drake, “who [unsuccessfully] claimed this territory as Nova Albion for the first Queen Elizabeth and for the queen’s successors forever”.
She then paid a visit to Reagan’s California ranch near Santa Barbara.
Torrential rains pounded the coastline and almost blocked the queen’s ascent to the mountaintop retreat.
But she finally made it in a Chevy Suburban, which navigated the terrain described by the Los Angeles Times as “a narrow, twisting, steep obstacle course of flooded streams, washed-out sections, downed tree limbs and falling boulders”.
“She found the trip delightful and terribly exciting,” Elizabeth’s press secretary was quoted as saying.
Reagan had been eager to impress her with his 278-hectare Rancho del Cielo and was surprised that the queen was not deterred by the weather.
“They made it up the mountain but when they got to our home, it was so foggy no one could see more than a few feet,” he wrote in his autobiography An American Life.
"I tried to explain how beautiful the place really was and apologised for the weather."
“But the queen said, ‘Yes, if it was just dreary, but this is an adventure'.”
She then ventured a little further north to San Francisco where six floors below the presidential suite of the St Francis Hotel on Union Square (now the Westin St Francis) were cleared to accommodate the royal couple.
The suite has since been renamed the Windsor Suite in honour of the visit.
The royals and the Reagans then had dinner and drinks at Trader Vic’s — the once famous, now-closed Tiki-themed restaurant.
The following day, at Davies Symphony Hall, Tony Bennett regaled the queen with I Left My Heart in San Francisco, alongside actress Mary Martin and young comic Robin Williams.
Reagan then hosted a dinner at the city's MH de Young Museum.
“I knew before we came that we had exported many of our traditions to the United States," the queen said in her dinner speech.
"I had not realised before that weather was one of them."
The visit also coincided with the Reagans' 31st wedding anniversary, which the couple did not mind celebrating with the queen aboard the Britannia.
“There were toasts and I said, ‘I know I promised Nancy a lot when we were married, but how can I ever top this?’” Reagan wrote.
Later that week, a pall was cast on the visit after three US Secret Service agents collided with a Mariposa County Sheriff’s Department car on a curvy California highway.
The agents, who were part of a detail protecting the queen, all died.