2000
#8,676
National surname rank
Recorded bearers 3,489
First available Census row
Per 100,000 1.29
Rare Last name
Glennon
Anglicized form of the Irish surname Ó Gleannáin, meaning "descendant of Gleannán," derived from the Gaelic word "gleann," meaning valley.
According to the 2020 US Census Bureau surname tables, roughly 3,801 Americans carry the last name Glennon. That puts it at #9,407 in the national surname ranking, appearing at a frequency of 1.11 per 100,000 people (about 1 in 90,175 residents).
This page is the full Name Census profile for the Glennon surname. You will find the Census Bureau frequency data, a multi-census history view, an ancestry and ethnicity breakdown based on self-reported demographics, the name's meaning and origin where available, and answers to the most common questions people ask about this surname.
For British records, Name Census UK has a British surname profile for Glennon with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
3.8K
1 in 90,175
Census rank
#9,407
2020 decennial data
Per 100,000
1.1
Frequency rate
Recorded bearers
3.3K
rare in the US
Popularity narrative
The Census Bureau recorded 3,315 bearers of the surname Glennon in its 2020 decennial surname file. At a rate of 1.11 per 100,000 residents, it holds the 9407th position in the national surname ranking.
Among Census respondents with the surname Glennon, the largest self-reported group is White at 92.2%. The next largest groups are Hispanic (3.8%) and Two or More Races (2.4%).
Origin
Meaning and origin of Glennon
The surname Glennon has its origins in Ireland, where it first emerged as a Gaelic Irish name during the Middle Ages. It is derived from the Irish Gaelic word "glennan," which means "glen" or "valley." This suggests that the name may have originally referred to someone who lived in or near a valley or glen.
One of the earliest records of the name can be found in the Annals of Ulster, a chronicle of medieval Irish history. The entry for the year 1395 mentions a Donaldus Glennan, who was likely an early bearer of the Glennon surname.
During the 16th and 17th centuries, the name Glennon was particularly prevalent in County Armagh and County Fermanagh, in the northern part of Ireland. It is believed that the name may have originated in one of these counties, where many families bearing the surname resided.
In the late 16th century, a notable figure named Hugh Oge Glennon was recorded as the chief of the Glennon clan in County Fermanagh. This suggests that the Glennons were a prominent family in the area during that time period.
Another historical figure with the Glennon surname was William Glennon, who was born in County Armagh in 1776. He was a prominent Irish Catholic priest and educator, and served as the president of the Royal College of St. Patrick in Maynooth, Ireland, from 1813 to 1837.
In the 19th century, the Glennon name spread beyond Ireland as many Irish families emigrated to other parts of the world, including the United States, Canada, and Australia. One notable bearer of the name was Richard Glennon, who was born in County Fermanagh in 1849 and later became the Archbishop of St. Louis, Missouri, serving from 1903 to 1946.
Other notable individuals with the Glennon surname include Brendan Glennon (1913-1995), an Irish playwright and novelist, and John Joseph Glennon (1862-1946), an American prelate who served as the Archbishop of St. Louis from 1903 to 1946.
While the Glennon surname has roots in Ireland, it has since become more widely dispersed across various parts of the world, with many families continuing to bear this name and its various spelling variations.
Demographics
Ancestry and ethnicity for Glennon
Among Census respondents with the surname Glennon, the largest self-reported group is White at 92.2%. The next largest groups are Hispanic (3.8%) and Two or More Races (2.4%).
The bar chart below shows how Glennon bearers described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given surname, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown for every Census year so the breakdown stays comparable over time. When the source file also includes raw headcounts, Name Census shows those alongside the percentages in the legend.
Keep in mind that these are self-reported numbers. A person's surname does not determine their race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the Glennon surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.2% · 3,058
- Hispanic or Latino3.8% · 127
- Two or more races2.4% · 78
- Asian and Pacific Islander1.1% · 36
- Black or African American0.4% · 13
- American Indian and Alaska Native0.1% · 3
Timeline
Historical Census data for Glennon
Glennon appears in 3 published Census surname files: 2000, 2010, 2020. The cards below show how the name's rank and bearer count changed across each release.
2010
#9,165
National surname rank
Recorded bearers 3,561
+72 bearers (+2.1%)
Per 100,000 1.21
Rank movement Down 489 places
2020
#9,407
National surname rank
Recorded bearers 3,315
-246 bearers (-6.9%)
Per 100,000 1.11
Rank movement Down 242 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #8,676 | 3,489 | 1.29 | First available Census row | First available Census row |
| 2010 | #9,165 | 3,561 | 1.21 | +72 bearers (+2.1%) | Down 489 places |
| 2020 | #9,407 | 3,315 | 1.11 | -246 bearers (-6.9%) | Down 242 places |
For 2020, the Census Bureau published race and Hispanic-origin columns as counts rather than percentages. Name Census converts those counts back into shares so the ancestry section stays comparable with the older surname files.
Year on year
2010 vs 2020 Census
How has the Glennon surname changed between Census years? The chart shows bearer count side by side, and the table compares rank, count, and frequency.
Census year comparison
20102020
| Metric | 2010 | 2020 | Change |
|---|---|---|---|
| Rank | #9,165 | #9,407 | -2.6% |
| Count | 3,561 | 3,315 | -6.9% |
| Per 100K | 1.21 | 1.11 | -8.3% |
Between the 2010 and 2020 Census, the number of Glennon bearers went from 3,561 to 3,315 (-6.9% change). The surname moved down 242 positions in the national ranking, going from #9,165 to #9,407.
FAQ
Glennon surname: questions and answers
How many people in the U.S. have the surname Glennon?
Name Census estimates that about 3,801 living Americans carry the surname Glennon. Using the current population baseline, that works out to roughly 1 in 90,175 residents.
How common is Glennon?
Glennon ranks #9,407 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.11 per 100,000 residents, which is about 1 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 3,315 people with the surname Glennon. That is different from the site's living-bearer estimate (3,801), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.11 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.11 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 1 of them to have the surname Glennon.
Has Glennon become more or less common over time?
Between 2010 and 2020, the surname Glennon went from 3,561 recorded bearers to 3,315. That is a decrease of 246 (-6.9%). In the national ranking it fell from #9,165 to #9,407.
What does the Census say about the background of Glennon?
Among Census respondents with the surname Glennon, the largest self-reported group is White at 92.2%. The next largest groups are Hispanic (3.8%) and Two or More Races (2.4%). These figures come from the 2020 Census Bureau surname tables, based on how respondents described their own race and ethnicity.
Which group reports this surname most often?
White is the largest self-reported group for the surname Glennon in the 2020 Census, accounting for 92.2% (3,058 people in the source table).
What is the full ancestry breakdown?
Glennon appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.2%), Hispanic (3.8%), Two or More Races (2.4%). For 2020, the source file also published raw headcounts for each group, which is why this page can show both percentages and counts in the ancestry section.
Is this page using the latest Census data?
Yes. This page is using the latest surname file currently loaded on Name Census, which is 2020. The historical section above also keeps any older Census surname entries we have for Glennon (2000, 2010, 2020).
Does the Census include every surname?
No. The Census Bureau only publishes surnames that appeared at least 100 times in a given decennial Census. That means very rare surnames are excluded entirely, and a surname can appear in one Census release but disappear from a later one if it falls below the reporting threshold.
Why don't the ancestry percentages always add up to exactly 100%?
There are two main reasons: rounding and suppression. The Census Bureau rounds published values, and it may suppress very small cells to protect privacy. For 2020, the Bureau also published raw group counts rather than direct percentages, so Name Census converts those counts back into shares for comparability across census years.
What does Glennon mean?
Anglicized form of the Irish surname Ó Gleannáin, meaning "descendant of Gleannán," derived from the Gaelic word "gleann," meaning valley. The fuller origin note on this page goes into more detail.
Where does the surname data come from?
All surname statistics on Name Census are drawn from the US Census Bureau's decennial surname frequency tables. These files list every surname that appeared 100 or more times in the 2020 Census, along with a count, a per-100,000 rate, and a self-reported demographic breakdown. You can read the full explanation on our methodology page.
How does Name Census estimate living bearers?
For surnames, Name Census does not age cohorts the way it does for first names. Instead, it takes the Census Bureau's published frequency for Glennon (1.11 per 100,000) and applies that rate to the current U.S. resident population to estimate how many living Americans have the surname today.
How many people are called Glennon?
Our sister site HowManyOfMe.org answers how many people have the surname Glennon at a glance, with the living-bearer count up front.