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(Click on picture to enlarge) Monaghan Coat of Arms

One-Name Study


About the Monaghan One-Name Study

My quest to find the Monaghans began while attempting to trace my Monaghan ancestor who was separated during his immigration to America from Ireland during the 1870s. The last living male descendant of my lineage passed away in 1996 so I have not been able to pursue his origin through Y-DNA. Although I am still researching my family, my research has transformed into a study of this surname through traditional research along with a DNA study. I encourage anyone with connections to a Monaghan-Monahan family to contribute to this study if possible. Any contributions you can make will be very valuable and greatly appreciated.


Accepted spellings of this surname vary to the extent that almost any vowel can be used in each vowel-position of the name. In addition to those variations, many have dropped the g, and some have dropped the ‘h’ from the traditional spelling. Most commonly you will find the following variations of the surname Monaghan.

Monahan / Monegan /Monehan / Minihan / Moynihan / Monk / O’Manacháin

Origin of the surname

According to the Irish Times website, Monaghan (or Monahan) is the English version of the Irish Ó Manacháin, from a diminutive of manach, meaning 'monk', and some of the family adopted the semi-translation Monks or Monk.

Most people with this surname in Ireland are believed to be descended from a warrior named Manacháin. During the middle of the 6th century AD, the king of Connaught kept twelve officers as his entourage, they were chosen from the leading clans of his country and their role was to attend on his person, give him counsels and help him to rule and govern the land. The O’Manachain clan was one of twelve who were initially appointed to these positions. The Monaghan family ruled an area known as The Three Tuathas or Ui Briuin na Sionna, and lived near the river Shannon (presently in County Roscommon) until the year 1249 when they were ousted by the O'Beirnes and appear to have diminished in power thereafter.

The surname is believed to be the source for County Fermanagh in Northern Ireland, which means 'Place of the Men of Manacháin.” Although this surname shares the same spelling, it is not related to County Monaghan in Ireland, which is derived from the Irish word Muineachán meaning 'a place abounding in little shrubbery.'

The family crest is made up of a gold chevron and three gold stars on a background of blue with an armored soldier above. An image of the family crest can be seen in the top right corner of this page.

Historical occurrences

Some notable Monaghans throughout history include:

Manachain, a noted Connacht warrior from the ninth century in the area of what is now Galway and Mayo.

Dick Monk, also known as Richard Monaghan, fought with the Irish rebels in the battle of Arklow in 1798.

James Clarence Mangan was a famous Dublin poet born in 1803.

James Henry Monaghan was a controversial Catholic Attorney General during the Young Ireland Movement who later became the Chief Justice that tried the Fenian rebels.

James Monaghan was a noted Irish American poet born in 1862.

Frequency of the name

Today, the Monaghan surname is most predominantly found in Ireland, followed by Australia, the United Kingdom, New Zealand, and Canada.

The Monahan surname is most predominantly found in Ireland followed by the United States, Australia, Canada, and New Zealand.

Distribution of the name

Irish Times reports that there were 1,022 Monaghan households in the Primary Valuation property survey of Ireland conducted between 1848-64. Counties reporting more than 50 households .

Fermanagh 120 / 11.74%

Galway 119 / 11.64%

Mayo 111 / 10.86%

Meath 99 / 9.69%

Cavan 84 / 8.22%

Tyrone 62 / 6.07%

Monaghan 54 / 5.28%

A surname distribution map for Monaghan families, created by Dr. Tyrone Bowes, Ph.D., indicates that the 1911 census reflected a similar distribution of Monaghan families with a slight decline found in County Fermanagh.

DNA project

There is a DNA study for Monaghan-Monahan family members, both male and female. If you would like more information regarding the DNA study, please visit our page at World Families DNA Project.


World Families DNA Project

My Mysterious Monaghan

Contact details

For further information, contact:

Lauren Ciarochi

This page last updated 10 February 2014.

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Profiles of other one-name studies registered with the Guild may be found here.

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Long thin blue line © Guild of One-Name Studies 2007 This page was last modified 10 Feb 2014, 19:08
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