The Clan/Sept History

The original Gaelic form of the MacGeoghegan surname is Mag Eochagain, a
patronymic derived from the personal name Eochaidh.

The illiterate population found in Ireland during the Middle Ages could only
define their names orally. The archives that survive today demonstrate the
difficulty experienced by the scribes of this period in their attempts to record
these names in writing. Spelling variations of the name MacGeoghegan dating from
that time include Geoghegan, Gagahan, Gahagan, Gahaghan, Gaghan, Gegan,
MacGeoghegan, Geohan and many more.
First found in the county of WestMeath, in the barony of Moycashel at Kilbeggan
where they held a family seat from ancient times. Traditionally, the
MacGeoghegans are said to descend from Fiacha, son of Niall of the Nine
Hostages.
The 18th century saw the slow yet steady emigration of Irish Families to British
North America and the United States. Those early Irish settlers that left their
homeland were typically moderately well off: they were enticed by the promise of
a sizable plot of land. However, by the 1840s, this pattern of immigration was
gone: immigrants to North America were seeking refuge from the starvation and
disease that the Great Potato Famine of that decade brought. The great numbers
of Irish that arrived to the United States and the soon to be Canada were
instrumental in their quick development as powerful industrial nations. An
examination of early immigration and passenger lists uncovered many early
immigrants bearing the name MacGeoghegan: Michael Geoghegan, a Scotch-Irish who
arrived in Boston in 1737; Edward Geoghegan, who came to Philadelphia in 1741;
John McGeogh, who arrived in America in 1742.