This bell-top shako cap was worn by officers in the County Constabularies and Irish Constabulary during the 1820s and 1830s. The early constabularies were armed with carbines, trained in drill and garrisoned in barracks, similar to light infantry regiments. The shako cap was a popular form of military headdress. An ornate felt version with regimental badge was worn by armies across Europe. The constabulary shako cap was more practical. Covered in oil cloth, it was waterproof for patrol duty and braids designating the rank of the wearer were its only decoration.

The Constabulary Act (Ireland) 1822 established the County Constabularies to work along side the Peace Preservation Force controlling agrarian disturbance and political unrest in Ireland. The County Constabularies were supervised by four provincial inspectors under the direction of Dublin Castle (the administrative centre of British rule in Ireland). The government believed that policing in Ireland needed greater uniformity and established the Constabulary Act (Ireland) 1836. This act abolished the Peace Preservation Force and brought the four provincial sections together in one national body (excluding the Dublin City and several town forces).