An additional 54 horses have flown from Australasia and South America for the Games.
The Irish horses' journey began last Wednesday when they left the final training camp to travel to Liege airport in Belguim where they were loaded onto a nine hour flight to Cincinnati, where they then spent 42 hours in quarantine before the last leg of the journey - the 45 minute drive to the Kentucky Horse Park. The horses were under the care of Horse Sport Ireland's team vet Marcus Swail, who travelled with them.
Britain's eventing horses travelled by road and ferry to Liege, in Belgium, and will fly to Cincinnati early on Wednesday morning. The riders will fly out on Friday.
Mary King has taken her ride, Imperial Cavalier, plus Tina Cook's Miners Frolic and William Fox-Pitt's Cool Mountain in her lorry to Liege. She said: "I just can't wait; I've been looking forward to this for years. 'Archie' has his bags packed and is ready to go. My groom, Jodie Summer, is beside herself with excitement as this is her first trip abroad with a team."
The second convoy of horses - Pippa Funnell's Redesigned, Nicola Wilson's Opposition Buzz and Piggy French's Jakata - travelled to Belgium in Pippa's lorry.
"I'm excited, but I'm also rather nervous now. I'll be happy once I know the horses have arrived and are settled," Funnell said.
This will be Nicola Wilson's second team appearance for Great Britain. "Opposition Buzz is fitter than he's ever been. He's got everything he needs in his flight bag and quarantine trunk. We've done all we can to prepare and I can't wait to get out there now and get started," she said.
World Class Performance Manager (Eventing) Yogi Breisner added: "We have a very exciting team with a nice balance between experience and youth in terms of riders and horses. We know the venue well and we are delighted to be going out to compete at such a wonderful place."
The competition starts on Thursday, September 30, with two days of dressage. The cross-country phase takes place on Saturday and the final show jumping phase on Sunday, October 3.
Ireland's show jumping horses will leave for Kentucky on September 27, as the show jumping does not begin until October 4.