The O'Donnell Castle Donegal Town was built on the shores of the river Eske, on a curve, just where the river meets the head of Donegal Bay, at the scenic Eske estuary. That was a highly strategic location in a number of ways...
River Eske flowing past Donegal Castle
From a defense point of view, it was ideal. The river served as a natural moat to the west, north, and northeast.
In the event of a security breach, it would have been easy to escape the castle up or down river, as well as by land.
The river provided the castle kitchen with a constant supply of salmon and other fish. Eske is an anglicized version of the Gaelic word 'iasc', which means 'fish'. This river was so-called for its abundance of fish.
Donegal Town was a bustling, vibrant center of two-way international commerce, which the Chieftain controlled from his castle.
Spanish galleons and other foreign ships delivered cargoes such as leather, wool, cloth and wine to the nearby wharf. Those were exchanged for Atlantic fish and other local wares, which were then shipped to Belgium for North European distribution.
Europeans called the O'Donnells 'Kings of the Fish'!