From Killala, Humbert advanced quickly. Ballina fell with little resistance. On 27 August, at Castlebar, Humbert's small force of French regulars and untrained Irish recruits faced a much larger British army under General Gerard Lake. What followed was so swift a rout that the British retreat became known across Europe as the Races of Castlebar. Lake's men ran for thirty miles. The defeat panicked Dublin Castle and London, and Cornwallis himself moved out with overwhelming reinforcements. On 8 September at Ballinamuck in County Longford, Humbert was finally surrounded and forced to surrender. The French were treated as prisoners of war and exchanged. The Irish were not. Many were hanged or transported. On 23 September, government forces under Major-General Eyre Power Trench retook Killala from the last of Humbert's rear guard - the final land engagement of the rebellion.

In the centre of Killala stands a round tower twenty-five metres tall, the last surviving fragment of a medieval monastery thought to have been built in the twelfth century. The tower is made of limestone. Round towers like this one are particular to Ireland - tall, slender, conical-roofed bell towers that doubled as places of refuge during Viking raids. Killala's tower has stood through nine centuries of weather, rebellions, and reformations. The monastery itself is gone. The bishop's seat is gone in any meaningful sense - though the Cathedral Church of St Patrick, built in the 1670s, still stands beside the tower. Together they mark a religious site Tradition associates with Saint Patrick himself, who appointed Muiredach as the first bishop of Killala in the fifth century.

Local tradition holds that Patrick baptised twelve thousand converts at a well near Killala on a single day. The well still flows. Whether or not the number is literal, the story carries the symbolic weight of Patrick's mission and the speed with which Christianity took hold along this stretch of coast. North Mayo was an early Christian stronghold. The pattern of churches, holy wells, ogham stones, and round towers across this part of Ireland reflects what the Irish themselves once called the Island of Saints and Scholars - though the saints came with conviction and not always with gentleness, and the conversion of a people from one religion to another is rarely as clean as the story makes it sound.

On 2 January 1893, after two years of construction at a cost of £29,000, a branch railway opened between Ballina and Killala. The line ran six miles, with five gatehouses, one tunnel, and four bridges. At Killala station there was a turntable, two sidings, a signal cabin, and a stationmaster's house. The line was meant to open the small port to the wider economy. It never quite paid for itself. Passenger services ceased on 1 October 1931. Goods continued until 1 July 1934, then stopped. The track was eventually pulled up. The stationmaster's house is now privately owned. In the 1970s, the Japanese chemical company Asahi built an acrylic fibre plant south of the village. Materials came from Dublin Port by rail to Ballina, then by road. The plant closed in 1997. The wind farm and battery installation now on the site mark Killala's third or fourth industrial attempt - the kind of cycle that defines small towns waiting for the next thing.

In 1981, RTE produced a television series called The Year of the French, based on Thomas Flanagan's novel of the same name. Killala was a primary filming location - the village standing in for itself. In 1989, the sculptor Carmel Gallagher unveiled a bust of General Humbert in the area to mark the upcoming bicentennial. In 1998, on the two-hundredth anniversary of the landing, Killala twinned with the French commune of Chauve. Each August, the bicentenary commemorations remind the village of those thirty-two strange days when it was, in a sense, French. The tricolour returns briefly. The harbour where Humbert came ashore looks much as it did. The story stays close, refreshed each generation, still alive in the village it briefly liberated and then, just as briefly, lost.