For the first time in 22 years since the establishment of UNIFIL, Irish and other UN troops yesterday patrolled right up to the Israeli border.
They moved past fortifications and posts abandoned and destroyed by the Israeli Defence Forces (IDF) and its proxy local militia, the South Lebanon Army (SLA).
Over the coming months, the UN will establish "forward" posts. From these bomb disposal teams will pick through the debris of abandoned Israeli positions, clearing them of mines and unexploded ordnance.
Minefields surround many of the hilltop fortifications and it may take many months before these are cleared.
UN sources here say there is unlikely to be an early withdrawal of UN forces due to the size and complexity of the problem of overseeing the initial resettlement of the former Israeli-controlled area (ICA).
However, the multi-national peacekeeping force comprising battalions of Indian, Fijian, Nepalese, Ghanaian, Polish, Finnish and Irish troops is now, finally, facing an end of the task set by the UN Security Council in May 1978.
The departure of Israeli troops followed by the sudden collapse of the SLA has suddenly provided the prospect of the closure of a mission which had seemed one of the most enduring and intractable ever undertaken by the UN.
For several years, the UN has been reducing its force in Lebanon as demands have grown from peacekeeping missions around the world.
After three days of frenetic activity, the area around the Irish Battalion position finally fell quiet yesterday morning as the Israeli withdrawal was completed.
Officially described as "calm", the quiet of the evening was shattered at around 7.30 p.m. local time last night as another of the hated compounds occupied by the Israeli forces was destroyed by a huge explosion.
The compound destroyed was just north of the Irish Battalion area. Four of the compounds abutting the Irish area were destroyed in similar fashion on Tuesday.
As dawn rose the last Israeli soldiers passed through a gate in the border fence just outside the northern Israeli town of Metulla, west of the Irish Battalion area.
The UN's immediate concern now is for the safety of occupants of the Israeli-controlled zone should Muslim extremists seek retribution for the violence inflicted on Lebanon during Israel's 22-year occupation.
By yesterday, local press reports suggested that some 2,400 people, about two thirds of the former pro-Israeli SLA, had surrendered to Muslim forces or the Lebanese army in southern Lebanon.
The first group of these had presented themselves at a joint Irish Battalion and Lebanese Army checkpoint - known as Total for its location beside a filling station - outside the village of Tibnin on Monday morning.
This was followed by the swift collapse of the entire military infrastructure of the Israeli-controlled zone, culminating in yesterday's dawn withdrawal through the Metulla gate.
On Tuesday, there was a traffic jam at the crossing because of SLA soldiers and their families fleeing possible retribution.
An estimated 5,000 Lebanese have now moved into northern Israel seeking refuge. The Israeli government yesterday said they would be offered tourist visas enabling them to work.
The speed with which the IDF completed the withdrawal is seen here as an indication of how relieved it is to be finally out of Lebanon.
The IDF has lost an estimated 1,200 troops, including a senior liaison officer, Brig Gen Erez Gerstein, last year, during its occupation of Lebanon, an occupation which has also led to the loss of thousands of Lebanese lives. In its last major bombardment of the countryside around this area on April 18th, 1996, Israeli shelling of a UN camp in the village of Qana caused the deaths of 110 Lebanese civilians, mostly women and children.
It was this atrocity which led Israel to accept the establishment of an international commission to prevent attacks on civilians by the combatant parties in south Lebanon.
Since Israel's acceptance of the so-called April 1996 "understanding", UN sources here say its withdrawal from Lebanon became an inevitability.