Parades and events marking St Patrick's Day have been taking place at home and abroad.
With many businesses and schools closed down for the bank holiday, tens of thousands of people have been taking part in the celebrations.
The biggest parade in the country took place in Dublin. An estimated 700,000 people turned out to see the event, which involved 3,000 participants and 17 international marching bands.
As the celebrations continue, gardaí say they are not expecting a repeat of the violence and public disorder that they had to deal with last St Patrick's Day.
There have so far been 18 arrests in the city centre, a similar number to what would be expected on an average weekend night.
In Cork, organisers of the Parade of Dreams re-invigorated the spectacle honouring the city's title as European Capital of Culture this year. An estimated 80,000 people came out to watch the spectacle.
The parade opened the city's first ever three-day Festival of St Patrick, and included outdoor musical and theatrical events throughout the city.
Over 70 different groups and organisations were represented, including a large gathering of performers and musicians from Northern Ireland.
Among Lord Mayor Councillor Sean Martin's guests on the viewing stand were the Duke and Duchess of Gloucester and the British Ambassador, as well as members of Belfast City Council.
Two grand marshals for Limerick parade
The theme of Limerick’s parade was ‘One City – A World of People’. For the first time the parade had two grand marshals, Limerick fashion icon Celia Homan-Lee, and former Munster rugby captain Jim Williams.
Over 40,000 gathered on Limerick’s O’Connell Street for the parade, which saw over 60 floats, groups and bands taking part.
Gardaí estimate that upward of 40,000 people attended the main parade in Waterford City.
The parade concentrated on the quays with a special maritime theme for the forthcoming tall ships, which are coming to Waterford in July.
In Galway gardaí say 100,000 people attended the city’s parade, which was the biggest in the history of the city.
Fifty groups took part and the parade took over two hours to cover the mile-long route through the city.
Open-air concert in Belfast
The focus of celebrations in Belfast was around City Hall, where three parades converged for a free open-air concert. In Armagh the emphasis was on religious services, underlining the city's status as ecclesiastical capital.
The biggest cross-community carnival in the North took place in Downpatrick, where St Patrick is reputed to be buried.