McDermott As An Irish Last Name

This article looks at how common McDermott is as a last name in Ireland and the United States from the 19th century to the present day.

You’ll learn the meaning and origins of the McDermott surname while exploring some notable and famous people that held it.

I use census records, emigration lists, and military archives to uncover fascinating patterns. If you’re studying your genealogy, check out my sources at the end of the post so you can do your own research.

How Common Was McDermott In Ireland In The Early 1900s?

Only the full censuses from 1911 and 1901 in Ireland are available to the public.

Earlier decades were either destroyed by the government (to make room for more storage) or by a huge fire during the Irish Civil War. Later decades are unavailable under privacy laws.

So, let’s focus on the early 1900s.

I used online archives to calculate the total numbers by surname. I consider these estimates due to some percentage of transcription errors. So, I’ve rounded the numbers to the nearest fifty.

There were 6,900 residents named McDermott on the island in 1911.

Ten years earlier, McDermott had about 7,200 residents in the 1901 census.

Population Estimates In The 1890s

A study of Irish surnames was conducted in 1890 by the head of the Civil Registrations Office. It was published as a “Special Report on Surnames In Ireland.”

The survey estimated that there were about 8,400 people named McDermott in the country.

Emigration To America After The Irish Famine

The Irish diaspora is large and widespread with a significant number of people emigrating to other parts of the globe. The destinations traditionally have been England, the U.S., Canada, and Australia. Emigrants were driven by various factors like political unrest, poverty, and food scarcity.

The peak of this migration was driven by what’s known as the Great Irish Famine, a devastating event spanning from 1845 to 1852. Potato blight had a catastrophic effect on Ireland, wiping out the primary food source for a significant portion of the population.

I reviewed the McDermott name in the shipping passenger lists arriving in New York during this period. The departures were from both Ireland and England.

This picture shows how the numbers rose and fell in the years after the famine:

McDermott emigration after the famine

How Common Is McDermott In The U.S.?

Based on the 2010 U.S. census, the name McDermott ranks about 1,190 among Irish names in America with 30,528 bearers.

Although the 2010 census has exact numbers and rankings, the rank I assign here is my estimate. If you’re curious about how I got there, here’s a brief explanation…

Estimating Rank In The United States

Historically, some Irish families with Gaelic surnames took English-sounding names as translations under the influence of colonization.

As these names also have English origins, they will have been brought to the United States by both British and Irish immigrants. Because the census doesn’t ask about specific European origin (e.g. England vs Ireland), it’s impossible to identify the proportion with Irish heritage.

I reviewed the census to identify which names are predominantly Irish in origin. In order to estimate the relative rankings of “Irish” names, I’ve mostly excluded surnames that have varying origins.

McDermott In Historic Times

In a country as young as the United States, tracking the popularity of a surname over time can be fascinating. This reflects other demographic shifts across the country in addition to immigration. Higher child mortality rates and longer life expectancy are just two factors.

The historic census records have been transcribed and digitized. I used online archives to run counts of surname populations.

But the totals can’t be exactly accurate due to transcription errors. So, I’ve rounded the numbers to the nearest 50 in the graph below.

This picture shows the numbers every twenty years from 1860 to 1940:

how common was McDermott in the U.S. between 1860 and 1940

These are the numbers in the graph:

  • 1860: 3,250
  • 1880: 8,500
  • 1900: 13,650
  • 1920: 16,650
  • 1940: 19,100

McDermott In World War II

Approximately 8.3 million men and women joined the United States Army during World War II. Many had Irish ancestry. Some had been born in Ireland before leaving the country.

There were registration records for 1,309 soldiers named McDermott who enlisted between 1938 and 1946.

There were 20 who were born in Ireland.

McDermott Surname: Meaning And Origin

McDermott comes from the Gaelic name Mac Diarmada. The “Mac” in Irish names literally means “son of”, so the name translates to “son of Diarmad.” The personal name Diarmad was anglicized to the similarly sounding name Dermot.

A powerful early Diarmad lived in the 12th century and was a great-grandson of Tadhg O’Connor, an 11th-century King of Connacht. Diarmad’s descendants took the name Mac Diarmada (later to become McDermott). As allies of the O’Connors, the clan was powerful in its own right.

The McGraths were hereditary poets to many of the ancient Irish clans. The McGraths were found in many different parts of Ireland, but the four main branches were located in the regions of Tipperary, Clare, Waterford, and Donegal.

Famous Or Notorious McDermotts

Here are some notable people with the family name:

  • Eugene McDermott (1899 – 1973): a geophysicist from Dallas who invented several devices for oil exploration and founded the company Texas Instruments.
  • Beverly McDermott (1928 – 2012): a casting director from Florida whose work included the films Scarface and Cocoon, and the television series Miami Vice.


External Research

The Ireland 1990s estimates are from Seán J. Murphy’s research paper.

The population estimates of 1890 are based on the “Special Report on Surnames in Ireland“, published in 1909.

The population figures for the 2010 U.S. Census come from a file provided by the U.S. Census Bureau.

Internal Research

Some of the population numbers are based on my own research and calculations using online archives. I’ve rounded those numbers to the nearest 50 to account for transcription errors and other technical issues with online databases of this type.

The Irish census estimates for 1901 and 1911 are my calculations based on the Irish National Archives

I plotted the emigration figures from 1845 to 1854 based on calculations from the archives of the New York Passenger Lists (1820-1957).