The 18-year-old became the first British female to win a Grand Slam singles title in 44 years, in a 6-4 6-3 victory over Leylah Fernandez.
Raducanu became the first qualifier to ever win a grand slam and was victorious in all 20 sets she played in qualifying and the main draw at Flushing Meadows.
“I send my congratulations to you on your success in winning the United States Open Tennis Championships,” a message from The Queen to the teenager read.
“It is a remarkable achievement at such a young age, and is testament to your hard work and dedication.
“I have no doubt your outstanding performance, and that of your opponent, Leylah Fernandez, will inspire the next generation of tennis players. I send my warmest good wishes to you and your many supporters.”
Who else has sent tributes?
Prime Minister Boris Johnson paid tribute to Toronto-born Raducanu, he wrote on Twitter: “What a sensational match! Huge congratulations to Emma Raducanu. You showed extraordinary skill, poise and guts and we are all hugely proud of you.”
The Duke and Duchess of Cambridge also hailed the achievements of the teenager, who moved to England with her Romanian father and Chinese mother at the age of two.
“Huge congratulations Emma Raducanu on your stunning performances and historic Grand Slam victory!” the Duke and Duchess of Cambridge wrote on Twitter.
“Incredible – we are all so proud of you. Leylah Fernandez well done on your amazing achievements at this year’s US Open , it’s been a pleasure to watch. C” they added, signing the tweet with an initial from the duchess.
A growing list of celebrity fans has also added their voices to the list of congratulations.
Pop group The Spice Girls tweeted: “Wow! Amazing tennis from @LeylahFernandez and @EmmaRaducanu that’s Girl Power right there!! Congratulations Emma.”
England football captain Harry Kane was quick to pay tribute to Raducanu, tweeting: “Amazing achievement @EmmaRaducanu. Done yourself and the whole country proud. Congratulations!”
The first minister of Scotland, Nicola Sturgeon, added her congratulations.
“Just incredible! @EmmaRaducanu is a star, a role model and a champion. Congratulations!” she tweeted.
“I suspect tonight is one of these sporting occasions that will be talked about for decades to come.
“Two great players who will no doubt dominate women’s tennis for years to come.”
TV presenter Gary Lineker said: “First time in my life I’ve ever tweeted whilst on air but my goodness what a performance, what a triumph, what an amazing young woman.”