Thousands enjoyed the music at Belfast's open air concert

Belfast hosted the largest parade on Wednesday with thousands gathering at the City Hall for a free open air concert.

Chart topping pop band Girls Aloud headlined the event.

The largest cross-community parade included up to 80 floats and 2,000 participants in Downpatrick.

St Patrick's Square is hosting a week-long festival to commemorate the saint who is buried in the town.

Tommy Griffin from Edinburgh said he was looking forward to his first St Patrick's Day in Belfast.

"I have been here a couple of times before but never on St Patrick's Day so I'm really looking forward to the concert, it will be great," he said.

His friend Lucille Murray from Keady in County Armagh said the atmosphere was "brilliant".

We come in to the city every year because it's great craic Michael Walsh

"We started the celebrations in Dublin yesterday but we decided to come here today to see what it's like in Belfast for a change."

Pauline Burns from west Belfast brought her two young daughters and her niece into the city for the first time.

"I am normally working so this is the first year that I'm actually off. We normally stay up the west but this is great," she said.

Lee and Ryan Walsh enjoyed the fun with their parents Michael and Janet Walsh.

"We come in to the city every year because it's great craic," said Michael.

The crowd get into the St Patrick's spirit at Belfast's open air concert

"The kids love it and it really is a great day. We'll spend the day here and hope the boys don't get too tired by it all."

In Enniskillen, 34 organisations took part in the town's second parade following the town's immensely popular inaugural event last year.

An Ulster Scots group provided entertainment in the town's Diamond while face painting and fire blowing kept young families enthralled.

In County Tyrone, the celebrations took place at the Ulster American Folk Park near Omagh.

The centre featured a re-enactment of the great American wake, which was commonplace in homes throughout the province when families left for America during the Famine.

The Omagh Community Arts Initiative took part in Dublin's parade where its all-singing, all-dancing performance Bohemian Rhapsody in Wonderland saw rock group Queen merge with the children's fairtyale, Alice in Wonderland.

Miss World Rosanna Davison leads the Dublin parade

They were one of 3,500 performers in the city's parade which included samba bands and elaborate floats.

Derry City Council invited the internationally acclaimed traditional musician Sharon Shannon to help them celebrate.

Irish dancers backed by the Emerald Ceili Band kicked off the proceedings at the city's Guildhall Square before the award-winning accordion player took to the stage.

In County Antrim, the annual climb of Slemish Mountain has been taking place, where willing participants could avail of a park and ride facility from Ballymena to the site where St Patrick is believed to have been a slave when he first came to Ireland.

The sound of traditional harp and fiddle music was enjoyed at the town's Ecos centre where children faced the challenge of a Shamrock trail.

Live music kept party goers in Armagh entertained with BBC Radio Ulster broadcasting live from the city.

Children from local schools prepared floats and costumes for a Mardi Gras-style carnival, depicting scenes from St Patrick's life.

A cultural evening of Ulster Scots music and dance was another feature of the city's week-long festival.