The Crossbarry Ambush on March 19, 1921 in the village of Crossbarry, twenty kilometres south-west of Cork city was one of the largest engagements during the Irish War of Independence between the Irish Republican Army and the British Crown Forces. An IRA column, 100 strong, under Tom Barry and Liam Deasy escaped from an encircling manoeuvre by 1,200 British troops, killing between 10 and 30 of them.
The increasing success of the West Cork Brigade of the Irish Republican Army led to a spate of arrests and interrogations of suspected IRA volunteers in West Cork in an effort to ascertain the identities and headquarters of those engaging in guerrilla warfare against the British forces. On February 15 1921, the IRA mounted an abortive ambush of a troop train at Upton, in which six civilians and three IRA men died. Several other volunteers were captured. The British succeeded in breaking an IRA volunteer under interrogation (via torture) and discovering that the West Cork Brigade had its headquarters in Ballymurphy. In addition, the British learned that Barry's column had recently returned to this area after several days waiting for an ambush on the Kinsale to Bandon road. The British commanders, as a result planned a major operation to capture the IRA column, mobilising about 1,200 troops, to converge on the area from several different directions. According to Tom Barry, 400 British troops came from Cork, 200 from Ballincollig, 300 from Kinsale and 350 from Bandon. Later in the day about 120 Auxiliaries also left Macroom. The sweep was mounted early in the morning of the 19th. At Crossbarry, some of the troops descended from their lorries to proceed on foot or by bicycle to catch the IRA unaware.
One early victim of the action was Charlie Hurley, the IRA Officer Commanding of the Cork Number Three Brigade. Hurley was trapped in a house and killed at about 6:30am. Tom Barry, only becoming aware of the danger at the last minute, resolved that his men, about 100 strong, would have to fight their way out of the encirclement. Barry's calculation was that his men, who had only 40 rounds per man, could not sustain an all day fight, which they could expect if they retired before the British. Moreover, the likelihood was that the small column would be trapped if it took this course of action. However, Barry observed that one of the British columns advancing towards Crossbarry was well ahead of the other British units. If his men could break through this British force, roughly the same strength as his own force, then they could break out of the British encirclement.
Barry laid out an ambush for the British at Crossbarry cross roads - his men being in position by 5:30 am. When the first British lorries, about 12 vehicles according to Barry's account, reached Crossbarry, they were caught by surprise and hit by a crossfire at very close range (5-10 yards or c. 5 metres). They took significant casualties and many of them fled the scene. Barry's men collected the British arms and ammunition before setting fire to the lorries. At this point, they were attacked again by another British column of about 200, coming from the southwest, but they too retired after a stiff fire fight. Two more British units converging on the area from the southeast tried to dislodge the IRA from their ambush position, but again without success and they too retired in disorder. Taking the chance offered by his quick victory to get away, Barry then marched his men to safety in the Gurranereigh area, while the British were still disorientated by the ambush. There was another brief exchange of fire at long range as the IRA column got away. The action had lasted for under an hour. Major Percival of The Essex Regiment on realising what had happened rushed to the scene with his troops, but was only able to open a long range fire on the fleeing IRA men. He later blamed the action on the Auxiliary column which had gone to the wrong rendezvous point and had therefore left a gap in the encirclement. There were some further combats along the IRA column's line of retreat at Crowhill and Rearour but with no further casualties on either side
Barry reported that three of his men were killed in the fight and another three wounded. British accounts claimed that six IRA men had died. The IRA claimed that over thirty British soldiers were killed in the action. The British admitted to only ten killed and three wounded . The RIC memorial records that one RIC constable and six soldiers were killed.