The Queen, accompanied by the Duke of Edinburgh, is to go on a four-day state visit to the Republic of Ireland on 17 May, Buckingham Palace has said.
The tour, announced last month, will include a ceremony in Dublin's Garden of Remembrance and a visit to the Taoiseach at Government Buildings.
The Queen will also make a speech at a state dinner at Dublin Castle.
It is the first state visit to the Irish Republic by a British monarch since independence.
King George V was the last reigning monarch to visit the country in 1911 when it was then part of the UK.
The Queen was invited to Ireland by the Republic's President, Mary McAleese, who will formally welcome the monarch at her home in Dublin's Phoenix Park, the Aras an Uachtarain.
The trip will combine visits to historically significant sites with tourist attractions.
The BBC's royal correspondent Nicholas Witchell said the most notably symbolic event was the ceremony at the Garden of Remembrance, where all those who gave their lives in the cause of Irish freedom and stood against the Crown are commemorated.
He said it was not known whether the Queen would lay a wreath.
In Dublin, the Queen will attend events at Trinity College Dublin, the National War Memorial Gardens in Islandbridge and at Croke Park stadium.
The ground is the home of Gaelic football where, in 1920 during the Irish War of Independence, British forces fired into the crowd at a football match, killing 14 spectators and players.
The Gaelic Athletic Association pledged to give the Queen a warm welcome to the 82,000-seater stadium.
"We are confident this historic visit to Croke Park will be welcomed by those who play, administer and support our games, at home and abroad, including of course throughout Britain," the organisation said.
There are also plans for the Queen and the duke to visit the Irish National Stud in Kildare, as well as Cashel, in County Tipperary, home to the popular tourist destination of the Rock of Cashel, and Cork.
The British ambassador in Ireland will host an event celebrating the monarch's return visit.
Security on the trip is expected to be tight, particularly in light of the recent murder of Constable Ronan Kerr in Northern Ireland.
The BBC's Ireland correspondent Mark Simpson has called the state visit a "watershed moment" in British-Irish relations.
The war of independence and use of the British army in the Troubles in Northern Ireland strained relations between the UK and the Irish Republic for much of the 20th Century.
The Queen also suffered personal loss when an IRA bomb blast killed her cousin Lord Louis Mountbatten on his boat in Ireland in 1979.
Sinn Fein President Gerry Adams said the party was "aware of the offence the visit will cause to many Irish citizens".
"Sinn Fein wants to see the normalisation of relationships between our two nations and republicans have been in the leadership of this process, but that can only be based on mutual respect and equality and on the ending of the partition of Ireland," he added.
Separately, Clarence House has announced Prince Charles is to make a short official visit to the US, also in May.
He will travel to Washington, where he will meet US President Barack Obama at the White House.
He will also give a keynote speech at a conference on sustainable agriculture at the city's Georgetown University and attend an event to support British and US armed forces deployed overseas.