Private Seán Rooney of the 121st Infantry Battalion has been buried with full military honours at Newtowncunningham.
His funeral mass took place in Dundalk, his birthplace, earlier on Thursday Dec 22.
Afterwards the funeral cortege made its way, with army escort, from Dundalk to Newtowncunningham.
Special clearance was given for the army in uniform to cross the border and the cortege was guided by motorcyclists from the PSNI through Tyrone to Lifford.
Along the way flags flew at half mast, and many came and stood in silence as the cortege passed.
At the morning’s funeral mass his mother Natasha McCloskey told how her son Seán, her first child, gave her a purpose in life, and told of how kind and loving he was.
Holly McConnellogue, Seán’s fiancée from Derry, said she was “absolutely honoured” to have had three wonderful years with him.
At Newtowncunningham, Pte Rooney’s coffin was carried on a gun carriage to the cemetery at Colehill.
To the graveside, his coffin was carried by members of the 27th Infantry Battalion. A piper led the procession.
Pte Rooney’s beret, the tricolour and the United Nations flag that draped the coffin were presented to his family: his mother Natasha, his father Paul, grandparents Eugene and Rachel, grandmother Ann McClosky, sisters Robyn and Carragh, brothers Callum and Benn and fiancée Holly.
Pte Rooney has been posthumously awarded the United Nations Medal along with the War Medal, the Wounded Medal, and the Appreciation Medal Bronze Degree from the Lebanese Armed Forces.
His funeral mass in Dundalk was attended by President Michael D Higgins, Taoiseach Leo Varadkar, Tanaiste Micheal Martin, Lt Gen Seán Clancy, Chief of Staff, Defence Forces, and political and social leaders.
Fr Derek Ryan said Pte Rooney’s death “really did pierce the heart of his family” and the wider community.
“It breaks the human heart when a loved one dies serving their country for the important work of peacebuilding.
“The pain of losing Sean so suddenly, and so tragically, is the greatest pain you can experience as a family, and as a community, and as a country.”
Pte Rooney, 24, had been looking forward to coming home from Lebanon for Christmas.
On Wednesday December 14 last, he was killed during an ambush while serving with the 121st Infantry Battalion on a UN peacekeeping mission.
He joined the Defence Forces at 19 and trained as a specialist driver at Aiken Barracks in Dundalk.
He was stationed in Lebanon in 2021.
This year, however, he went back to Lebanon in order to save up for his planned wedding next summer.
Also, during the ambush Pte Shane Kearney, 22, from Killeagh, Co Cork, suffered a serious head injury.
Two other peacekeepers have been treated for minor injuries.
A total of 333 Irish soldiers are in south Lebanon as part of the United Nations Interim Force in Lebanon.
Eighty-eight personnel, 87 from the Irish Army and one from the Irish Air Corps, have died in overseas service since the 1960s. Forty-eight soldiers have died in Lebanon.