The name Langan is a contraction and Anglicisation of the Irish (Gaelic) name, Ó Longáin, meaning grandson (or descendant) of Longáin. Longáin is thought to mean long or tall.
According the local Ballycastle lore, six Langan brothers arrived from Donegal in the 18th century and settled in Doonfeeny and the Ballycastle area. The six Langan brothers are credited with building the picturesque Palmerstown bridge about 1788, which was subsequently used by General Humbert's invading French troops that came to assist the Irish rebellion in 1798. Langan was a relatively common name in County Mayo by the time of the Griffiths Valuation (c1850), with 77 families recorded. The author's Langan ancestors come from Ross, Ballyknock (Townland), in Doonfeeny parish.
The following lists indicate how common each of the above surnames was by county during the 1848-1864 Griffiths Valuation. If the surname is very rare, then you can be more certain that a name which matches your ancestor's is more likely to be the correct person. If the name is common, then you may need more details to verify the match. This information is available for most surnames at the Irish Times web site.
Famous Langans associated with County Mayo
The Irish full-forward Gaelic footballer Tom Langan (1921-1974) was born and raised in Ballymacue (Ballycastle), County Mayo. Ronan O'Gara the Irish Rugby star and record points scorer, is Tom Langan's first-cousin-twice-removed, and is also descended from the County Mayo Langans. Both are descended from the common ancestor, Patt Langan c1800, whose descendant chart is shown below.
Ancestry of "The Great Tom Langan" (Gaelic footballer)
LanganHouseholds by County in 1864
Clare 1 Cork 3 Donegal 30 Dublin 26 Dublin city 13
Galway 12 Kerry 12 Kildare 10 Laois 1 Leitrim 3
Limerick 5 Longford 16 Mayo 77 Meath 38 Offaly 3
Roscommon 7 Sligo 17 Tipperary 1 Waterford 9 Westmeath 20