Mrs Grimes was one of three generations of the same family murdered in Saturday's blast. The funerals of her daughter, Avril Monaghan, who was pregnant with twins, and of her 18-month-old grand-daughter, Maura, took place on Tuesday.
As she was laid to rest yesterday in her home village of Beragh, near Omagh, the Archbishop of Armagh, Sean Brady, told mourners to resist the temptation to give in to despair.
"That would be the final surrender to those who instil terror and inflict violence," Archbishop Brady, leader of the Catholic Church in Ireland, said during a requiem mass.
Mrs Grimes, who was married to a dairy farmer and had 11 children, was celebrating her 65th birthday on the day she died.
In Omagh itself, hundreds of mourners lined both sides of a street outside the home of a father and son killed by the bomb. The coffins of 60-year- old Fred White and his son Bryan, 26, were carried out of the family home side by side.
The mourners walked slowly behind the two caskets as the cortege wound its way away from the house, towards the tiny Creevan Presbyterian Church just a couple of miles away. The two men were buried at the Old Drumragh cemetery.
Among the mourners were the First Minister, David Trimble, and his fellow Ulster Unionists Ken Maginnis and Willie Thompson. Fred White had been a member of the party.
At the funeral service, the Rev Arthur O'Neill described the bombing as "an act of medieval savagery".
Meanwhile, on the outskirts of Omagh, more than 300 people gathered in a small Church of Ireland church to pay respects to 15-year-old Lorraine Wilson, an Oxfam shop volunteer .
Louise's coffin was carried to the edge of the estate where she lived and then driven through the devastated town to Cappoagh parish church, in the surrounding countryside.
The Right Rev Dr James Mehaffey, Bishop of Derry and Rathoe, told the congregation that she had been an example to others in the way that she had given her time so freely for charity.
Alan Radford, 16, was another Omagh High School pupil who was buried yesterday. He had been due to collect his GCSE results yesterday. His father, Melvin Radford, 53, a former soldier who survived an IRA attack, travelled to Northern Ireland from his home in South Yorkshire to attend the funeral.
Mr Radford was critically injured 10 years ago when a terrorist bomb ripped through his unmarked Army van.Reuse content