Queen Elizabeth was in Kenya when she received the news of her father's passing and her ascension to the throne. She was on a royal tour with her husband, Prince Philip, Duke of Edinburgh.

On February 6, 1952, while staying at the Treetops Hotel in Aberdare National Park, word arrived that her father, King George VI, had died in his sleep. Princess Elizabeth and Prince Philip were informed of the news early in the morning.

This unexpected turn of events meant that Princess Elizabeth, who was only 25 years old at the time, became the new Queen of the United Kingdom and the other Commonwealth realms.

Despite being in a remote location, Queen Elizabeth immediately began her reign. She chose the regnal name "Elizabeth II" to honor her father, King George VI. A simple proclamation was drafted and signed in Kenya, officially declaring her as Queen.

It is worth noting that the Treetops Hotel, where Queen Elizabeth was staying, has become a historic landmark. Visitors can now stay in the same room where the future Queen received the news of her accession.

References:

1. "The Treetops Hotel." Aberdare National Park. https://www.aberdarenationalpark.org/the-treetops-hotel/
2. "Queen Elizabeth II becomes the longest-reigning UK monarch." BBC. https://www.bbc.com/news/uk-34177112