Breogán son of Brath (Briganos Maccos Brattae in Gallaic) was a mythical Celtic king from Galicia. Various accounts exist of this mythological father of the Galician nation. His sons were Ith and Bile (Belenus). Bile was the father of Mil Espaine.
Galicia itself is sometimes described poetically as the "home of Breogán" (or, in Galician, the fogar de Breogán). The land is so described in the anthem of Galicia, "Os Pinos".
According to Gaelic legends compiled in the eleventh-century Lebor Gabála Érenn ("The Book of the Taking of Ireland", also called "The Book of Conquests" or "The Book of Invasions"), King Breogán constructed in Brigantium (an ancient Celtic town, whose location is nowadays unknown, but maybe Betanzos or A Coruña) a massive tower of such great height that his sons Ith and Bile could see a distant green shore from its top. The glimpse of that distant green land enticed them to sail north to Ireland. Once there, they were received by the Tuatha Dé Danann (an ancient tribe who occupied Ireland before the Celts), who ambushed them and managed to kill one of Breogan's sons, Ith. Decades later, Míl Espáine took vengeance upon the Tuatha Dé Danann and invaded Ireland with the intention of defeating them and settling in Ireland.
This tale is mostly described in the last chapter of the Lebor Gabála Érenn in reference to the Milesians or "Sons of Míl" who, were the last wave of invaders according to Irish mythology.
A similar story about a monk who saw a green island from the top of the tower of Brigantia was written in the ninth or tenth century in Galicia. The manuscript is called Trezenzonii de Solistitionis Insula Magna ("Trezenzon the Monk and the Big Island").
A large statue of Breogán has been erected near the Tower of Hercules.
In Madrid, Spain's capital, there is a park called Parque de Breogán, named after Breogán.