A branch of the Irish National Volunteers was formed in Straffan in 1914. The St Anne's Brass Band from Ardclough played at the Bodenstown commemoration in 1914 at which Thomas Clarke spoke. In February 1917 a Company was reformed in Straffan and a branch of Sinn Féin formed in 1918. Volunteers planned to bomb the bridge at Straffan but the plan was aborted. Telephone wires were destroyed at Bishopscourt and Straffan volunteers took part in the ambush at Stacumny on 5 July 1921. Prominent local volunteers included John Logie, Tom Cornelia, James Travers and John McSweeney. During the Civil war the barnewall homestead near the 13th Lock in Lyons was the North Kildare brigade headquarters for the anti-treaty IRA.