Dennis

An Irish surname of Cork and Dublin. In the 2010 US census it was carried by 78,482 people, the 409th most common surname in the country.

Dennis is the anglicised form of two distinct Irish names. Some you can hear in the English name; others look and sound nothing like it, and were simply swapped for it.

Mac Donnchadha, Mac Donnchaidh, son of Donnchadh (brown warrior, or strong warrior, an ancient and very common Irish personal name, anglicised Donough, Denis). This family stood in Co. Clare, Co. Cork, Co. Limerick, and Co. Sligo.

Ó Donnghusa, descendant of Donnghus (brown-choice). This family stood in Co. Cork and Co. Waterford.

Where the name comes from

Dennis is Donnchadh, the brown or strong warrior, one of the ancient and very common Irish personal names, anglicised both Donough and Denis. Mac Donnchadha names at least three distinct families.

One is a branch of the MacCarthys who were chiefs of Duhallow in Co. Cork and at one time very powerful, with their principal seat at Kanturk. One is a branch of the MacDermotts of Moylurg, chiefs of Tirerrill and Corran in Co. Sligo, who resided at Ballymote: the Book of Ballymote was compiled under their patronage. The third is a Scottish clan in Perthshire, said to be a branch of the MacDonalds, who now write the name Duncan and some of whom call themselves Robertson.

Ó Donnghusa, descendant of Donnghus, brown-choice, is an ecclesiastical family in Ulster and a Munster family chiefly in Cork and Waterford.

Rugged Atlantic coastline at Allihies, Cork, Ireland, with layered slate cliffs, fine art landscape photograph by Peter Cox
Allihies Coast, Cork

The Dennis counties, photographed

Cork

Cork is the largest county in Ireland. Three peninsulas run west into the Atlantic: Beara, Sheep's Head and Mizen, with the population thinning the further out you go. My gallery is in Glengarriff at the head of Bantry Bay, so it's the ground I photograph most.

Sunset over Dun an Oir ruins and sea stacks on Cape Clear Island, Cork, fine art landscape photograph by Peter CoxDún an Óir, Cape Clear Island, Cork Co. Cork The Fastnet Lighthouse standing proud on a calm summer evening off West Cork in black and white panoramic viewThe Fastnet Lighthouse, Co. Cork Co. Cork Aerial view of the Fastnet Lighthouse surrounded by angry seas off West Cork with Cape Clear Island on the horizonThe Fastnet from the Air Co. Cork Inside the rotating lantern of the Fastnet Lighthouse with Fresnel lenses, ladder, and a rainbow projected on a poleInside the Lantern, the Fastnet Lighthouse, Co. Cork Co. Cork The winding Healy Pass road climbing through the Caha Mountains on the Beara Peninsula, Cork on a cloudy dayThe Healy Pass, Co. Cork Co. Cork Long exposure of a small pier extending into a bay at sunset under heavy cloud, Lehanbeg, CorkLehanbeg Pier, Co. Cork Co. Cork Sunrise over Gougane Barra lake with mountains reflected in still water, County Cork, Ireland — fine art landscape photograph by Peter CoxA Morning at the Office, Gougane Barra, Co. Cork Co. Cork Long exposure of waves crashing against rocks at the Old Head of Kinsale lighthouse at dusk with its lantern shiningOld Head of Kinsale Lighthouse, Co. Cork Co. Cork

Dublin

Dublin is a county as well as a city. The bay has Howth at the north end and Killiney Hill at the south, the Muglins are a pair of rocks off Dalkey, and the Dublin Mountains start about half an hour from the city centre.

Moonlight reflecting on the sea near the Muglins lighthouse off Dalkey Island, Dublin, with the Kish light on the horizonThe Muglins by Moonlight II Co. Dublin Long exposure panoramic view of the White Rock swimming platform at Killiney Bay, Dublin, floating in misty high-tide watersThe White Rock, Killiney Bay, Co. Dublin Co. Dublin Heron fishing at dawn on the Dublin coast — fine art wildlife photograph by Peter CoxHeron, Co. Dublin Co. Dublin

All Cork prints · All Dublin prints

Notable bearers

Sandy Dennis (1937-1992), film actor, television actor, and stage actor.

Ron Dennis (born 1947), businessperson and entrepreneur.

Rohan Dennis (born 1990), sport cyclist, athlete, and track cyclist.

Emmanuel Dennis (born 1997), association football player.

Clare Dennis (1916-1971), swimmer.

About this page

The counties on this page are where the name was thickest on the ground in Ireland a century and a half ago, not a claim about any one family. Names moved around inside the country as much as they left it. The photographs are mine, made in the counties named.

How common the name was

In 1890, 10 births were registered under Dennis in Ireland, most of them in Cork and Dublin.

Leinster 4
Munster 4
Connacht 1
Ulster 1
Ireland 10