The IRA established a police presence in the county and intimidated individuals suspected of having intentions to join either the Army or the RIC.

In July 1920, the Black and Tans were deployed to the county, and "began to engage in wholesale intimidation and violence against civilians without any provocation."

However, as noted by historian Thomas Earls Fitzgerald, IRA activity consistently increased in spring of that year, being bolstered by the arrival of Andrew Cooney from Dublin in February 1921, who formed a flying column on 2 March and made plans to launch attacks against British forces.

2 Kerry Brigade launched a successful ambush on a British Army convoy, killing several soldiers including Brigadier-General Hanway Robert Cumming.

[3][4] Upon hearing of news of the ambush, Chief of Staff of the Irish Republican Army Richard Mulcahy, who was impressed with the IRA's performance in County Kerry, wrote to the officer commanding of the No.

"[5] On 21 March, an IRA party of the 2nd Kerry Brigade commanded by Tom McEllistrim and Dan Allman were billeted about four miles from the Headford railway junction when they heard that British troops were returning by train from Kenmare to Tralee.

Allman, commanding 30 volunteers, reached the junction only 12 minutes before the train, which was carrying 30 soldiers of the 1st Battalion of the Royal Fusiliers.

[7] One of the first British casualties was Lieutenant CE Adams DCM,[8] who was shot dead when he appeared at the carriage door, as were several other soldiers who were standing in front of the engine.

[10] McEllistrim called on the survivors to surrender and when they refused, the IRA began to move in to finish off those who kept shooting, by throwing hand grenades under the train.