The Queen is to meet victims of the Omagh bomb amid tight security on her Golden Jubilee visit to the North.
She will also make an address to the Northern Ireland Assembly at Stormont.
At Hillsborough, the Queen will officially confer city status on two communities, Newry in Co Down and Lisburn in Co Antrim.
The Queen, accompanied by the Duke of Edinburgh, will meet victims of the 1998 Omagh bomb and other atrocities, including the 1987 Enniskillen "Poppy Day" bombing, at a garden party in Loughry College, Cookstown, Co Tyrone.
Twenty nine people, and two unborn twins, died after the Real IRA placed a 500lb bomb in Omagh on August 15, 1998.
Eleven people were killed by an IRA bomb at Enniskillen, Co Fermanagh, on November 8, 1987, when they waited for a Remembrance Sunday ceremony to begin at the town's war memorial.
The Queen's 15th visit to Northern Ireland marks her 50th year on the throne and every available police officer is expected to be on duty as the Queen and Prince Philip carry out engagements in four counties - Tyrone, Fermanagh, Antrim and Down.
Her Golden Jubilee speech at Stormont's Parliament Buildings is the first time the Queen has addressed the Northern Ireland Assembly since it assumed devolved powers from Westminster in December 1999.
The SDLP is expected to be present, signalling the nationalist party's fullest involvement in a Royal visit.
Sinn Féin, although not objecting to the Royals visiting Northern Ireland, says it will stay away.