The name Eoin is derived from the Gaelic Eógan, which originated in Ireland in the early medieval period. It is the Irish equivalent of the name Eugene, stemming from the Greek Eugenios, meaning "well-born" or "noble". The name gained widespread usage among the Gaels, particularly in the western regions of Ireland.

One of the earliest recorded instances of the name Eoin can be found in the Annals of Ulster, which chronicle events in medieval Ireland. The annals mention an individual named Eógan mac Conaill in the 7th century, who was a prominent king of the Cenél Conaill dynasty in present-day County Donegal.

The name Eoin has been associated with various notable figures throughout Irish history. One of the most renowned was Eoin Ruadh Ó Néill, also known as Red Hugh O'Neill (1550-1616), a celebrated Irish chieftain and military leader who spearheaded the Nine Years' War against English rule in Ireland.

Another prominent bearer of the name was Eoin Buitléir, or Owen Butler (1671-1719), an Irish Jacobite soldier and statesman who played a significant role in the Williamite War in Ireland and later served as a member of the Irish Parliament.

In the realm of Irish literature, Eoin MacNeill (1867-1945) was a prominent scholar, writer, and co-founder of the Gaelic League, an organization dedicated to the preservation and promotion of the Irish language and culture.

The name Eoin has also been associated with religious figures, such as Eoin Ó Conchobhair (1570-1635), an Irish Franciscan friar and Archbishop of Armagh, who played a crucial role in the Counter-Reformation in Ireland.

Eoin Cholm Ó Cianáin (1775-1861) was an Irish poet and scribe who is renowned for his contributions to the preservation of Irish literature and language in the face of English suppression.