Polling stations closed at 10pm tonight after 15 hours of voting in the Lisbon Treaty referendum, the result of which will determine the future development of the European Union and its institutions.
Voting began at 7am and statons in 43 constituencies were open until 10pm to encourage as many people as possible to vote.
Both the No and Yes sides of the treaty debate expressed confidence today that the result will go in their favour, but the result may be tight with 17 per cent of voters still undecided in a poll last weekend.
The result is expected by late afternoon tomorrow.
Turnout was reported at about 40 per cent by 9pm, up from 20 per cent in some constituencies by mid-afternoon.
In general, turnout was reported to be higher in city areas than in rural areas.
In Dublin, the area of Mulhuddart in west Dublin had a turn out in the early 40s. In Walkinstown, turnout was reported to be up to 50 per cent, an hour before the polls close at 10pm.
Skerries in north Dublin had a turnout of about 46 per cent, while Dun Laoghaire in the south of the county had a showing of about 49 per cent by late evening.
In other parts of Leinster, Navan polling stations reported turnout of just over 40 per cent.
However, some parts of the busy commuter town had turnout as low as 20 per cent by late this evening and presiding officers did not expect that to rise by much.
Dundalk, Co Louth also had a turnout in the low 40s. In Letterkenny, a late showing by voters pushed turnout up to about 41 per cent. Turnout in parts of Leitrim also hit the mid-40s.
It was reported the constituency of Limerick East was set to hit a turnout of 50 per cent by closing time at 10pm.
In Taoiseach Brian Cowen's constituency of Laois-Offaly, turnout was running at between 16 and 25 per cent at lunchtime but was expected to rise.
In some areas, including Waterford, returning officers described turnout as slower than usual for a referendum.
Turnout traditionally picks up in late evening as those returning from work head to polling stations to cast their votes.
For first time in the State's history, more than three million voters were eligible to cast their ballots in a European referendum. The electorate stands at 3,051,278 as of February 15th, 2008.
Every person who is an Irish citizen and is included in the register of electors, which came into force on February 2008, 15th, is entitled to vote. Those included in the supplement to the register can also vote.
Those casting their ballots may be asked to show a passport, driving licence, employee identity card or student card. They will be given a white ballot paper, and those who approve Ireland's ratification of the treaty should mark 'X' in the square beside "TÁ/YES" while those against it should mark 'X' in the square beside "NÍL/NO".
The full text of the constitutional amendment, as outlined in the Bill, will not be on the ballot paper but will be available for inspection at polling stations.
The State's voters were encouraged by those campaigning for and against the Lisbon Treaty to go to the polls today to cast their ballots on what Taoiseach Brian Cowen described as an important date in Irish history. Ireland is the only EU country to hold a referendum on the treaty, with other states ratifying it in parliament.
The Taoiseach cast his vote in Mucklagh National School in Tullamore, Co Offaly, at 10am.
Brian Cowen refused to comment directly on the referendum result but said he was confident.
“It is an important issue for the country . . . a referendum by its nature is about change in our constitution, and our citizens should take that seriously, and hopefully, as I said, as many people as possible come out to vote,” Mr Cowen said.
Referring to the campaign, the Taoiseach said: “I led it as best as I possibly could. We’ve conducted a positive campaign, an honest campaign.”
Mr Cowen said the No campaign had not conducted such a campaign “given the level of misrepresentation and worries that people were articulating to me in response to issues that clearly weren’t in the treaty at all”.
Fine Gael leader Enda Kenny voted at the Powers Centre, Castlebar, Co Mayo, while Labour leader Eamon Gilmore cast his vote at Scoil Mhuire National School, Shankill, Co Dublin.
Speaking after he voted, Mr Kenny said the referendum was a "moment of truth, an exceptionally important day for the people of Ireland.
"I hope that as many [voters] as possible turn out. I think that there has been a change of attitude in the last 10 days in that people have begun to focus on the reality of what the treaty is about, what it means for this country, what it means for Europe and the challenges that we face within the European Union and beyond on a global scale".
After he voted, Mr Gilmore refused to discuss in detail the campaign, saying: “All of these questions are for tomorrow or for the postmortem.”
When asked if the change of Taoiseach midway through the campaign affected the running of campaign, he said: “My views on that are on the record”. Mr Gilmore has previously stated that Fianna Fáil started the campaign belatedly.
“If it goes through there will probably be no mortem and no post, and if it’s a No, well, we’ll have a review. As you know, the Labour Party always has a review after an election,” Mr Gilmore added.
Earlier today, Sinn Féin Dáil leader Caoimhghín Ó Caoláin voted at St. Patrick’s Hall, Monaghan town. Dublin MEP Mary Lou McDonald vote at 11am in Scoil Thomais, Castleknock, Dublin.
Ms McDonald said she believed the vote would be very tight and that the Yes camp probably believed it had the edge. However, she said the most important thing on polling day is that Irish people get out and exercise their democratic right.
"This is a very important vote, it is to ammend the constitution and whatever way people have decided, it is abslutely critical they come out and vote.
"I hope we have a big turnout, I hope the rain holds off and anyone who is waivering I would encourage them to come out and use their democratic right and cast their vote.
"People are sovereign in these matters. It is not for political parties to decide, these are unique opportunities for people to exercise their democratic voice," she said.
Declan Ganley of anti-Lisbon group Libertas and his wife, Delia, arrived just before 10.30am to vote in Brierfield National School near Horseleap Cross in north Co Galway.
Speaking to The Irish Timesafterwards, Mr Ganley said he felt Libertas had provided "a good debate".
“Ireland is the only country to have a referendum, although the French and Dutch did vote on a predecessor of this Treaty. Whatever the outcome, this is the voice of the Irish people speaking, and it’s a good day for democracy here in Ireland,” he said.
Mr Ganley expressed the hope that there would be a No vote which would send a “clear message to Brussels” for the need for democracy, accountability and transparency.
Asked if he would accept the outcome, Mr Ganley said that he would. “The voice of the Irish people is not to be questioned,” he added.
The votes from 43 constituencies will be counted at a number of centres tomorrow, Friday. At the completion of each count, each local returning officer will inform the referendum returning officer, who will be based at St Patrick's Hall, Dublin Castle, of the result from their constituencies.
The referendum returning officer will tot the constituency result and declare the overall result, which should be known by late afternoon.
A broadcasting moratorium on the Lisbon Treaty is in place, and all political activity will be prohibited close to the polling stations for the duration of the poll.
The prohibition on political activity applies to the grounds in which the polling station is situated and within 50 metres of any entrance to the grounds.
The moratorium is aimed at ensuring that fairness and balance are achieved by broadcasters during the referendum. It is also intended to allow voters a period of reflection in the final stages of the treaty debate.
Full coverage of the referendum results will be available on The Irish Timeswebsite (http://www.ireland.com/focus/thelisbontreaty) on Friday, with reports and analysis along with audio commentary from the count centre at Dublin Castle. Results from the count centres will be updated live throughout the day.