Owners and riders from across Ireland and the UK are competing at the Irish Pony Society Championship Show in County Fermanagh.
It is the first time the event has been held in Northern Ireland, with winners qualifying for the UK Horse of the Year show in Birmingham in October.
The two-day competition is being held at Castle Irvine on the Necarne Estate in Irvinestown.
Equestrian events have returned to the venue after a break of almost a decade.
In 2012, the Department of Agriculture, which leased the estate from Fermanagh District Council, decided Necarne was surplus to its requirements.
Two years ago, the lease was awarded to a local business and Castle Irvine has since hosted a variety of events, including car and motorbike shows, vintage fairs, and concerts as well as eventing and show jumping.
Clive Johnston, chairman of the Irish Pony Society, said it was their "main championship show".
He described Castle Irvine as a wonderful venue and said the feedback from competitors was that "they love it".
"As a backdrop it's just spectacular, the facilities are amazing, and it's a destination for competitors to come to and have a couple of days away," he added.
The competition includes lead reins and first ridden for young riders through to the best bred Connemara Ponies.
Amanda Torrens of the Irish Pony Society said part of its aims was to secure breeding into the future.
"We breed the best horses here in Ireland there's no doubt about that, but it's a lovely sport and lovely friendships are got within the sport," she said.
The 235-acre estate includes a 17th Century castle, an all-weather cross-country course, a 300-seat indoor show jumping arena, an outdoor walled garden arena and 80 stables.
Hannah Gallagher, Castle Irvine events organiser, said it had hosted 30 equestrian events already this year.
She said the aim was to see the return of international competitions such as the three-day International Eventing Championships which were last held at Necarne in 2009.
Ms Gallagher described it as a unique venue.
"We have people telling us about the memories they have and how happy they are to see the place reopened again," she said.
She added that people who have never been before were "using the estate daily now and are really enjoying it".
"It really is a place for people to enjoy," she said.