Carrick-on-Shannon is the county town of County Leitrim in Ireland. It is also the smallest main county town in the country. It is situated on a strategic crossing point of the River Shannon and is the largest town in the county. It has been regarded as the key to the west from Ulster for millennia as it is situated on a fording point of the Shannon.
In the vicinity of the nearby village of Drumsna, on the County Roscommon border, may be seen remains of an Iron Age fortification, which points to the long felt need to prevent incursions and raids from that quarter. As an ancient stronghold of the O'Rourkes of Breifne and their ofttimes rivals, the O'Raghnaills (Reynolds) of North Roscommon, the town was granted a royal charter and named a borough with its own seal in 1607.