From Irish inis meaning "island," also a place name in County Clare, Ireland.
Ennis comes from the Irish Inis, meaning "island" or more specifically "land between waters" — a riverside flat or a piece of ground embraced by a river bend. The town of Ennis in County Clare, the administrative capital of that county, takes its name from this geographic description: it sits at a ford on the River Fergus. Irish place names converted to given names carry a particular topographic poetry, rooting a person in landscape rather than lineage.
As a given name, Ennis has been used in Irish-American communities since the nineteenth century, when emigrants brought townland and county names with them as a way of carrying home across an ocean. It appears in birth records across Massachusetts, New York, and Pennsylvania in the decades after the Great Famine as families honored geography and memory simultaneously. The name gained a wider contemporary profile through the character Ennis Del Mar in Annie Proulx's 1997 short story "Brokeback Mountain" and Ang Lee's 2005 film adaptation — a portrayal of suppressed longing and quiet devastation that gave the name an indelible emotional association for a generation of readers and viewers.
Ennis sits comfortably in the current landscape of Irish-revival names — alongside Finn, Rían, and Cormac — while remaining less common than any of them. It has a spare, northern sound: one syllable short of elaborate, self-contained without being blunt. For families with Irish roots, it is a way of carrying geography; for those without, it is simply a clean and quietly powerful choice.