Almost 300,000 people are expected over the next three days at the National Ploughing Championships in Screggan, Co Offaly.
The gates have officially opened for the three-day event, which is one of the biggest annual outdoor events in Europe.
350 people will take part in ploughing events, while exhibits on site include everything from cookery demonstrations to sheep shearing.
Assistant Managing Director of the Championships, Anna Marie McHugh, explained: "I think there's a survival mode when you're at the ploughing - you're outdoors, and there's no event going to be tougher on that front than ploughing. An outdoor event in the autumn - in fairness, it's madness.
"But I think the combination of the exhibition and the competition... I do think that causes a little bit of an energy."
President Michael D Higgins is officially opening the championships today.
Government ministers will be among those attending over the next few days, while several Presidential nominees - including businessman Gavin Duffy and Senator Joan Freeman - will also be travelling to Co Offaly.
