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Belfast Lough, County Antrim/Down


Ir. Loch Lao ‘sea-inlet of the calf’



This may be among the earliest documented place-names names of Ireland.  It was recorded as Logia meaning 'female calf, heifer' in the Geographia of the Greek geographer Claudius Ptolemaeus (Ptolemy).  This work was compiled c. AD150, although the earliest surviving manuscript copies date from the 13th century.  Logia (fem.) is a very early form of a word meaning 'calf' which became lóeg in Old Irish and lao in Modern Irish (both masc.).  The Irish name, Loch Lao, has been very stable throughout history. It is recorded as Loch Laigh in the Annals of Tigernach under the year AD 272, and appears in contemporary Irish sources from the 7th century.  Ir. loch which commonly means ‘lake’ can also mean ‘sea inlet/estuary’. The river Lagan which flows into Belfast Lough was at an early period known as Lao ‘calf’, from the bovine goddess which was believed to inhabit it.  When the lough began to appear in English on late-16th century maps, it was associated with Carrickfergus which was then the principal town of the area, e.g. Knock Fergas Baye (SE Ulster map, 1580) or The Baye of Karegfergus (Mercator's Ulster, 1595).  This was superseded in the second half of the 18th century by Belfast Lough, the current English name, as Belfast developed with the linen industry and overtook Carrickfergus in size and importance.


McKay, P. (1999): A Dictionary of Ulster Place-Names, p. 21; with additions PT, 2012.

Additional Information

Historical name form

Old FormRef. DateReference

Λογια ποταμου εκβολαι (= Logia river-mouth) [O’Rahilly 1946: 3]


Loch Laigh

0161EA 272 [citing Annals of Tigernach]


0650cMon. Hib. 3

in stagno dimersis vituli, monacis.. Comg. [L.Laíg]

0690cAdomnán 490n 114a


0830cMon. Hib. 15

[bru] locha laig

0830cEA 272

Locha Laigh i n-Ultoibh, for brú

1170cMart. Gorm. Oct 16n p196

Locha Laigh in Ultoibh, for brú

1170cMart. Gorm. Oct 25n p202

Breasail Laig qui subintravit Loch Laig

1200cDescendants Ir ii 68

The bay of Cragfergus

1567Goghe's Map

lough magherghie [referring to Islandmagee, marked in wrong situation acc. to Benn]

1570cEarly Chart B'fast Lough (Benn) i 275

Knock Fergas Baye

1580cSE Ulster Map

Cnokfergus bay

1591Hondius Map

The Baye of Karegfergus

1595Mercator's Ulst.

Baiy of Knockfergus

1602-3Bartlett Maps (Esch. Co. Maps) i (Ulster)

Locha Laoigh i nUltoiph, for bru

1630cMart. Don. Oct 15 276

for bru Locha Laoigh, i nUltoibh

1630cMart. Don. Oct 25 p282

Loch Laodh

1647EA 273

Loch Loedh

1647EA 273


1650cMon. Hib. 15

Carreckfergus Lough

1693Collins B'fast Lough

Carickfergus Bay

1708Pratt's Tabula

Carickfergus Bay

1744Harris Hist. frontispiece map

The Lough and Harbour of Belfast [title of a painting by Paul Sandby, R.A.]

1750Owen, D.J. 1917 facing page 9

Carrickferges Bay

1759Jefferys' Ireland

Belfast Lough

1777Taylor & Skinner 5, 13

Belfast Lough

1780Lendrick Map

Belfast Lough

1791Williamson's Belfast

Belfast Lough

1793Taylor's Ireland

Lough Bannchor

1873Mon. Hib. 3

Loch Lao

1989GÉ 129

Loch Lao

1989GÉ 189

Loch Lao ""estuary of the Lao or Lagan""

1999Dict. Ulst. PN 21

Loch Laogh

3506AM [≈1694BC]AFM i 32
the bay or haven of Carrickfergus1604CPR Jas I 38b
Kncokfergus bay1605CPR Jas I 73b
the bay of Knockfergus1605Inq. Ant. (DK) 43,47,48
the bay of Knockfergus1605CPR Jas I 73a
the bay of Carrickfergus1606CPR Jas I 89a
Carrickfergus bay1608CPR Jas I 120b
the bay of Carrickfergus1608CPR Jas I 125b
the bay of Knockfergus1608CPR Jas I 120b
Knockfergus Bay1610Speed's Ulster
Knockfergus bay1611CPR Jas I 216b
the bay of Knockfergus1621CPR Jas I 523b
the bay of Carrickfergus1654-6Civ. Surv. 62a
Parish in 1851
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