The Delbna or Delbhna were an ethnic group in Ireland. Originally one large population, they had a number of branches in Connacht, Meath, and Munster in Ireland.
The Delbhna Tir Dha Locha (of the Two Lakes), or Delbhna Feadha (of the Heather), were based in the area of County Galway between Lough Corrib and Lough Lurgan/Galway Bay. Their chiefs took the surname MacConraoi, or MacConroy, later Anglicized to King. The MacConraoi held Gno Mor while their cadets, O'hEanna or O'Heney, held Gno Beg, but in the annals MacConraoi is always styled Ri or Tighearna Thira Da Locha.
The Delbhna Nuadat, or Delbhna Ui Maine, were lords of a large section that is now Athlone in County Roscommon, situated between the Suck and Shannon Rivers. From the early historic era they were a subject people of the Ui Maine. Their chiefs took the surname O'Flannagain or Flannagan.
The Delbhna bEthra may have once formed a single kingdom with the Delbhna Nuadat until subjugated by the Ui Maine. By the late 5th century they had fallen under the control of the Uí Néill. Their chiefs took the surname MacCochluinn or Coughlan, and their territory was what is now Garrycastle in County Offaly.
The Delbhna Mor were located in what is now Delvin in County Westmeath. Their chiefs took the surname O'Finnallain or Fenelon. They lived together with one of the seven branches of the Soghain.
The Delbhna Bheag, or Delbhna Bec, were based in what is now Demifore in County Westmeath. Their chiefs took the surname Ua Maoilchallan, or Mulholland.
The Delbhna Sith Neannta ruled over the area now called Fairymount in County Roscommon. Their chiefs took the name O'Laoghog or Logue.
The Delbhna Teannmhagh, or Delbhna Iarthair Mhidhe, at one time controlled what is now Rathconrath in County Westmeath. Their chiefs took the surname Ua Scolaidhe or O'Scully.
Central Ireland showing the approximate location of the various branches of the Delbhna