The name is derived from the Celtic goddess, Muma. The province was once divided into six regions Tuadh Mhuman (north Munster), Des Mhuman (south Munster), Urh Mumhan (east Munster), Iar mumhan (west Munster), Ernaibh Muman (the Ernai tribe's portion of Munster), and Deisi Muman (the Deisi tribe's portion of Munster). Ultimately, these were all subsumed into the kingdoms of Thomond (north), Desmond (south), and Ormond (east), all of which were eventually subsumed by surrender and regrant as Earldoms in the Peerage of Ireland. The names exist only indirectly today, particularly in the case of Thomond. The three crowns represent these three kingdoms, this flag can easily be confused with the flag of Dublin which has three castles in a similar pattern on a blue background.
Munster is the most southern of the provinces, consisting of counties Clare, Cork, Kerry, Limerick, Tipperary and Waterford.
In the divisions used before the arrival of the Normans, the province was divided into two, the northern kingdom of Thomond and the southern kingdom of Desmond, with the border running through the Slieve Luachra mountains.
Apart from the large towns of Cork, Waterford and Limerick, in the nineteenth century Munster was still a predominantly rural region, with a wide variation in prosperity, from the relatively fertile and wealthy areas of south Tipperary and east Cork, to the bare subsistence levels along the Atlantic coast in south Kerry and west Cork.