Hundreds of thousands of people have attended almost 120 St Patrick's Day parades of various shapes and sizes around the country.
The largest, in Dublin, attracted an estimated 600,000 people along the route. It started at Parnell Square and finished at St Patrick’s Cathedral. World boxing champion Katie Taylor was the grand marshal for the day.
The city centre was transformed into a sea of green leprechaun hats and tricolours for the two-hour spectacle of street theatre troupes, pageantry, dancers and marching bands. Moreover, to the crowd’s delight, the rain stayed away.
Susan Kirby, St Patrick’s Festival chief executive, estimated half a million people turned out. “We were very, very pleased with it,” Ms Kirby said.
“I think Dublin and its people looked very well. I would hope that if even for a short while we were putting our best foot forward and demonstrating what an optimistic country we are.”
For the first time a short story was the inspiration behind the parade, with Brilliant by Roddy Doyle chosen for the honour because of Dublin's designation as a Unesco City of Literature.
It tells the story of two children and the quest to banish the black dog of depression over the city - a reference to the financial woes facing the country.
Pageant groups - including City Fusion, Brighter Futures, LUXe, Macnas, Artastic, Inishowen, Spraoi and Bui Bolg - interpreted different chapters of the story.
Mr Doyle said he penned the piece while watching news reels of the International Monetary Fund arriving in Dublin last November. “It was a reaction to that really, that’s why I wrote the story,” he said.
President Mary McAleese joined other dignitaries and watched the parade from a stand at the GPO on O’Connell Street. Dublin Lord Mayor Gerry Breen arrived in a restored, gilded horse-drawn carriage.
International bands from as far afield as Spain, France and the United States wooed spectators, as Taylor led the parade through Dublin.
Caoimhe Stack from Minnesota, in Dublin visiting relatives, was enthusiastic about the parade. “It was so colourful and cultural, not like anything back home,” the 19-year-old said. “I didn’t expect anything like this. There was no advertising, just music, culture, dance and colour. It was definitely worth coming to.”
Nele Claes (30), from Luxembourg, said the parade "was very good, very nice, and they put a lot of work into it”.
Selected buildings in Dublin, including the Guinness Storehouse, are also lighting up green for the festival. Last year the St Patrick’s Festival provided an estimated €50 million in additional revenue for the capital.
Other events in Dublin today, as part of the five-day festival, include fun fairs at Merrion Square, Wolfe Tone Park, and Custom House Quay and music with the Kilfenora Céilí Band in the RDS.
There are also walking tours and free traditional music sessions.
Parades and events were also staged in cities and towns all over the country, including Cork, Waterford, Galway, and Belfast.
St Patrick’s Day is also being marked throughout Northern Ireland, most notably in Belfast, Armagh and in Downpatrick, where the saint is reputedly buried.
In Belfast, SDLP Lord Mayor Pat Convery led the city’s carnival parade at midday from City Hall to Custom House Square where a free outdoor concert and other festival events took place. The parade had the environment as its theme.
The Cork parade was the central event in the city’s four-day festival. It started at 1pm on Parnell Bridge, continuing to South Mall and finished on Parnell Place.
“Happiness” was the theme of the parade, which included arts group Spraoí, Cork Circus and Dowtcha puppets as well as over 2,000 community and voluntary groups.
In Galway city, up to 60,000 people attended the “World of Wonder” parade, which began at 12.30pm on Father Burke Road and finished at Eyre Square. Traditional music is being provided in the city as part of the festival’s Trad Trail.
An estimated 40,000 people attended the Waterford city parade, which was based on the theme of the return of the Tall Ships Race to Waterford.
The Limerick parade had 4,600 participants, the largest outside Dublin, and an estimated 70,000 people lined the route. Its theme marked the city’s reign as European City of Sport 2011.
St Patrick’s Day celebrations are also taking place in many cities in the United States, in England, in Australia, Europe and Asia.