A cumann (Irish for association; plural cumainn) is the lowest local unit or branch of a number of Irish political parties. The term cumann may also be used to describe a non-political association.
Traditionally Sinn Féin and Fianna Fáil have called their local branches by that term. Fine Gael also uses the term to describe its local branches in the Clare constituency.
In Sinn Féin, the principal units of the party are the cumann and the Comhairle Ceantair (area council), which consists of elected members from the area's cumainn. The Comhairle Ceantair is a form of district unit covering a number of cumainn over a geographic area (usually a County Council constituency). The Ard Comhairle functions as the Sinn Féin national committee and executive; it is composed of elected board members on an all-Ireland basis.
The structure of Fianna Fáil somewhat resembles that of Sinn Féin; the elementary units of the party are the cumann, the Comhairle Ceantair (area council) and the Comhairle Dáil Cheantair (constituency council). The Comhairle Ceantair is a form of district unit covering a number of cumainn over a geographic area (usually a County Council constituency), while the Comhairle Dáil Cheantair is a collection of all the cumainn or all the Comhairlí Ceantair in a Dáil (parliamentary) constituency.Basil Chubb, The Government and Politics of Ireland