Cassidy Surname Genealogy

The Irish surname Cassidy and its variants Cassiday, Casaday, Cassedy, and Casidy are anglicized forms of the Gaelic name O’Caiside, a derivative of cas, meaning “curly headed.”  The name originated in county Fermanagh. 
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Cassidy Ancestry

All Cassidys came originally from Fermanagh, where for centuries they
were prominent not in warfare but in peace, culture, and
scholarship.  Their ancient home was Ballycassidy, just north of
Enniskillen.  The bardic poet Giolla Mochuda Mor O’Casside was
famed among the men of learning of his time. He wrote the poem Banshenchas (The Lore of Woman) in
1147 which tells of the history of women in the world.

From the 1300’s, when the Maguires assumed control of Fermanagh, the
Cassidys acted as their hereditary physicians and were,
during that
time, the authors of several medical tracts.  They were also one
of the church families of Fermanagh.  However, after the Scottish
plantations in the early seventeenth century, the Cassidys, like nearly
all the leading Gaelic families in the province, lost their power as

There are still Cassidys in Fermanagh.  But many
moved away to the nearby counties of Meath, Cavan, and Donegal; and
others emigrated.

England and Scotland.

That Cassidys are to be found in Glasgow and Lancashire is not
surprising as these
were the closest immigrating points for Irishmen seeking a better
life.  This description of James Cassidy from Enniskillen may have
been typical of many who crossed the Irish Channel:

“James was an agricultural laborer and would have lived
with his family in a cottage made of rough stone with a thatched
roof.  There would have been separations for a kitchen and a
bedroom which allowed little for home comforts.  The food was
chiefly potatoes, fish, pottage, milk, butter, and eggs. As a farm
laborer, James was earning no more than 10d per day.”

James left Fermanagh in 1840 with his wife and three children for
Glasgow where they all worked in the cotton mills.  His grandson
was able to escape these mills.  James Rice Cassidy set up his
own theatrical company with his wife Lilian and
toured the north of England, to great acclaim, in the early

Another who made it was John Cassidy from county
Meath.  He had moved to
Manchester and became a well-known sculptor in the inter-war years through his various
public works.

America.  The first
arrivals may well
have been indentured
servants.  Catherine Cassidy was a servant of John Hutchins in
in 1703.

Cassity arrived later in the century.  His family moved onto
Kentucky in
the 1780’s.  Patrick Cassidy fought on the American side during
the Revolutionary War and was granted land in Newry, Pennsylvania
– which he named after his hometown in Ireland.

Many more Cassidys came in the 1840’s after the
potato famine and
again in the 1870’s and 1880’s.  These Cassidys settled for the
most part in the Irish communities in Brooklyn.

Two sons of these immigrants did well:

  • Lewis Cassidy, who moved
    with his family to Philadelphia at an early age, studied law and later
    became Attorney General of Pennsylvania.
  • John Cassidy profited
    more fortuitously.   He was paid handsomely for standing in
    as a Civil War volunteer in place of the Spreckels sugar fortune
    heir.  He invested his money in cottages on Shelter Island, a
    place which later became a fashionable gathering spot for New York

In the 20th century, from these roots, came the
actor Jack Cassidy and his actor/singer son David Cassidy.  Daniel
Cassidy, who grew up in a NY Irish neighborhood, compiled the 2007 best
seller, How The Irish Invented Slang.

The Cassidy claIm to Wild West fame is mainly fictional.  Butch
Cassidy of Butch Cassidy and the
Sundance Kid
was in fact born Robert Parker, the son of Irish
immigrants from Lancashire.  Hopalong Cassidy was the fictional
creation of Clarence Mulford.  But Neal Cassady, icon of the
1950’s Beat generation, had come from an Irish Quaker Casady family who
had immigrated to America in the early 19th century.

Canada.  William and Jane
from Donegal were early arrivals, in 1819, in St.
John, New Brunswick. They settled in what is now called Cassidy
Lake.  Although their original homestead has burnt down, there
remain the foundations, apple orchards, cemetery and church that they

Patrick and Margaret Cassidy came from county Cavan in the
1820’s.  They later moved on to farm in Illinois.  Thomas
Cassidy from West Meath appeared on the 1829 McCabe list of workers on
the Rideau canal to connect Montreal with Toronto. He and his family
stayed to farm in Wakefield township, Quebec.

New Zealand.  Thomas
Cassidy from county Meath was one of the earliest arrivals into New
Zealand.  He had been transported to Australia for seven years for
stealing a pig.  After serving his term he embarked for New
Zealand in 1829 and arrived in the north Auckland area where he married
the daughter of a local Maori chief.  From this marriage have come
a large number of descendants.

Hugh Cassidy from Donegal came to New Zealand in the 1860’s and ran
hotels and a coach service from Hokitika on South Island for many
years.  His son Michael ended up a lawyer and apparently a shrewd
one, “charging exorbitant fees to those who could afford them and
nominal ones to those who couldn’t.”

Select Cassidy Miscellany

If you would like to read more, click on the miscellany page for
further stories and accounts:

Cassidy Names

Giolia Mochuda Mor Ó Caiside was an early bardic poet of Ireland. 
Ó Caiside (Rory O Cassidy) was archdeacon of
Clogher Cathedral in the early 1500’s.  
Thomas Cassidy
, an expelled Augustinian friar and later soldier of
fortune, wrote a racy autobiography which was popular in Ireland in the
eighteenth century.
Lewis Cassidy rose to become the Attorney General of
Pennsylvania in the 1880’s.  
Con Cassidy
was one of the great Donegal fiddle players of the 20th
Cardinal Edward Cassidy, born in Australia, was
one of the leading
Vatican emissaries in the late 20th century.
David Cassidy of New York Irish roots is an American actor,
singer, and guitarist. 

Select Cassidys Today

  • 21,000 in the UK (most numerous
    in Lanarkshire)
  • 8,500 in America (most numerous
    in New York).
  • 18,000 elsewhere (most numerous in Canada) 




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