The first Saturday election for more than 100 years saw a change in voting behaviour - but the outcome is incredibly unclear.
Many polling stations recorded strong early turnouts and turnout is expected to be above 60pc.
The imminent arrival of Storm Ciara, Ireland's Six Nations clash with Wales in Dublin and a plethora of GAA fixtures around the country were seen as a significant factor in the busy morning activity.
Traditionally, when elections have taken place on Thursdays and Fridays, polling stations saw activity after 6pm. The switch to a weekend polling day saw people make use of the morning opening to prevent voting clashing with other weekend plans.
Voting has not taken place on a Saturday since 1918.
But the country is now facing the prospect of a hung Dail once the votes are counted. Lengthy government formation talks are likely to follow.
Fine Gael (22.4pc) Sinn Fein (22.3pc) and Fianna Fail (22.3pc) are level in terms of public support, according to the exit poll conducted by Ipsos MRBI for RTE, TG4 the Irish Times and UCD.
The results indicate that Taoiseach Leo Varadkar may have managed to claw back support for Fine Gael in the dying days of the campaign.
Fianna Fail will be particularly disappointed with the party's performance in the capital. Mr Martin knew that if he was to find an easy path to power, he would have to make considerable gains in Dublin. However, they appear to have only achieved 14pc, trailing Fine Gael on 21.1pc and Sinn Fein on 22.3pc.
Mr Martin's candidates did perform better in the rest of Leinster where they polled 26pc, four points ahead of Mr Varadkar's party. Sinn Fein were second in the 11 counties outside of Dublin on 24pc.
Fianna Fail and Fine Gael are neck and neck in Munster on 26pc and 25pc respectively. Sinn Fein are back on 18pc.
In Connacht-Ulster, Fine Gael edged in front marginally on 23pc, just a single point ahead of Fianna Fail. Sinn Fein are on 20pc.
The Green Party will be somewhat disappointed that despite much talk about climate action being a key factor in this election they have failed to make a major breakthrough outside of Dublin.
The party is on 12.9pc in the capital which means Eamon Ryan can expect to grow his Dail numbers - but it will be difficult to reach the 10 TDs many had predicted.
The Labour Party achieved 8.1pc in the capital but their overall projected share of 4.6pc means they have lost a third of their 2011 vote. Holding onto seven TDs looks like a long shot.
Fine Gael, whose campaign was marred by difficulties, were quick to react to the poll with party chairman Martin Heydon saying: "We are in the hunt in every constituency for seats and are determined to come out of this election as the largest party
"This is a very encouraging exit poll, but it is just that. While many were keen to write us off in this election, this demonstrates that Fine Gael retains the trust and support of a large swathe of the Irish public."
President Michael D Higgins and the leaders of the major political parties were among the early voters.
Mr Higgins was accompanied by his wife Sabina as they cast their ballots at St Mary's Hospital in Phoenix Park, a short distance from Aras an Uachtarain.
Fianna Fail leader Micheal Martin voted with his wife, daughter and two sons early at St Anthony's Boys National School in Ballinlough, Cork.
Taoiseach and Fine Gael leader Leo Varadkar is facing a difficult battle to hang on to power.
He brought a box of Roses for polling centre staff at Scoil Thomais, near his home in Castleknock, Co Dublin.
Before casting his ballot, he told the Sunday Independent how he would spend the day of reckoning. He attended Ireland's clash with Wales with his partner Matt Barrett before finding a way of killing time waiting for last night's exit poll results.
"Afterwards I'll visit some polling stations in my constituency to thank all the staff. They do a really long day. I reckon I'll go home and watch the exit poll on the TV at 10pm. That's if I don't get the heads-up in advance."
Sinn Fein leader Mary Lou McDonald was with local councillor Seamas McGrattan as she cast her vote at St Joseph's School in Dublin. She said it was an important day.
"Today is the day that people are in charge and every single vote counts," she said.
"People have told us throughout this campaign that they want change, that they want a change in our presentation and they want a change in government, so I am saying to people please come out today and vote for a change."
Recent opinion polls had showed a surge in support for her party but they faced criticism for its treatment of the family of the murdered Paul Quinn.
An IRA gang is believed to be behind the 21-year-old's killing when every bone in his body was broken. Sinn Fein had to apologise last week after the party's finance minister in Northern Ireland claimed Mr Quinn was involved in criminality.