2000
#8,607
National surname rank
Recorded bearers 3,518
First available Census row
Per 100,000 1.30
Rare Last name
Colgan
An Irish surname derived from the Gaelic "Ó Collagáin," meaning "descendant of Collagán," a personal name of uncertain origin.
According to the 2020 US Census Bureau surname tables, roughly 3,846 Americans carry the last name Colgan. That puts it at #9,313 in the national surname ranking, appearing at a frequency of 1.12 per 100,000 people (about 1 in 89,120 residents).
This page is the full Name Census profile for the Colgan 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 Colgan with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
3.8K
1 in 89,120
Census rank
#9,313
2020 decennial data
Per 100,000
1.1
Frequency rate
Recorded bearers
3.4K
rare in the US
Popularity narrative
The Census Bureau recorded 3,354 bearers of the surname Colgan in its 2020 decennial surname file. At a rate of 1.12 per 100,000 residents, it holds the 9313th position in the national surname ranking.
Among Census respondents with the surname Colgan, the largest self-reported group is White at 92.7%. The next largest groups are Hispanic (3.3%) and Two or More Races (2.5%).
Origin
Meaning and origin of Colgan
The surname Colgan originated in Ireland and is derived from the Irish Gaelic name "O'Colgan" or "Ua Colgan". It is an anglicized form of the old Irish personal name "Colgan", which means "young descendant" or "young offspring".
The Colgan name has its roots in County Sligo, Ireland, where it was first found in the baronies of Carbury and Dromahaire. The name is also associated with County Donegal in Ulster, where several prominent families bearing the name resided.
One of the earliest recorded instances of the Colgan name can be found in the Annals of Ulster, a chronicle of medieval Irish history, which mentions a "Colgan Ua Maelsechlainn" in the year 1022. Additionally, the name appears in the Annals of the Four Masters, another important medieval Irish text, in reference to a "Colgan Ua Clerigh" in 1196.
In the 16th century, the Colgan surname was well-established in County Sligo, with several notable bearers of the name. One such example is John Colgan (c. 1592-1658), an Irish Franciscan friar, historian, and hagiographer, who was born in Sligo and is known for his work on the lives of Irish saints.
Another prominent figure with the Colgan surname was Theobald Colgan (1630-1684), an Irish Franciscan friar and author. He was born in Donegal and wrote extensively on Irish history and literature.
In the 17th century, the Colgan name was also found in the Chancery Inquisitions for County Donegal, which were legal records documenting land ownership and inheritance. This suggests that the Colgan family had established landholdings in the region during that time.
The Colgan name has also been associated with various place names in Ireland, such as Colganstown in County Meath and Colganstown in County Kildare, indicating the historical presence of the family in these areas.
Other notable individuals with the Colgan surname include Sir John Colgan (1728-1805), an Irish politician and landowner from County Sligo, and John Colgan (1879-1957), an Irish journalist and writer who was born in County Donegal.
Demographics
Ancestry and ethnicity for Colgan
Among Census respondents with the surname Colgan, the largest self-reported group is White at 92.7%. The next largest groups are Hispanic (3.3%) and Two or More Races (2.5%).
The bar chart below shows how Colgan 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 Colgan surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.7% · 3,108
- Hispanic or Latino3.3% · 110
- Two or more races2.5% · 83
- Asian and Pacific Islander0.8% · 26
- Black or African American0.4% · 15
- American Indian and Alaska Native0.4% · 12
Timeline
Historical Census data for Colgan
Colgan 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
#8,965
National surname rank
Recorded bearers 3,651
+133 bearers (+3.8%)
Per 100,000 1.24
Rank movement Down 358 places
2020
#9,313
National surname rank
Recorded bearers 3,354
-297 bearers (-8.1%)
Per 100,000 1.12
Rank movement Down 348 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #8,607 | 3,518 | 1.30 | First available Census row | First available Census row |
| 2010 | #8,965 | 3,651 | 1.24 | +133 bearers (+3.8%) | Down 358 places |
| 2020 | #9,313 | 3,354 | 1.12 | -297 bearers (-8.1%) | Down 348 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 Colgan 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 | #8,965 | #9,313 | -3.9% |
| Count | 3,651 | 3,354 | -8.1% |
| Per 100K | 1.24 | 1.12 | -9.5% |
Between the 2010 and 2020 Census, the number of Colgan bearers went from 3,651 to 3,354 (-8.1% change). The surname moved down 348 positions in the national ranking, going from #8,965 to #9,313.
FAQ
Colgan surname: questions and answers
How many people in the U.S. have the surname Colgan?
Name Census estimates that about 3,846 living Americans carry the surname Colgan. Using the current population baseline, that works out to roughly 1 in 89,120 residents.
How common is Colgan?
Colgan ranks #9,313 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.12 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 3,354 people with the surname Colgan. That is different from the site's living-bearer estimate (3,846), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.12 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.12 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 Colgan.
Has Colgan become more or less common over time?
Between 2010 and 2020, the surname Colgan went from 3,651 recorded bearers to 3,354. That is a decrease of 297 (-8.1%). In the national ranking it fell from #8,965 to #9,313.
What does the Census say about the background of Colgan?
Among Census respondents with the surname Colgan, the largest self-reported group is White at 92.7%. The next largest groups are Hispanic (3.3%) and Two or More Races (2.5%). 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 Colgan in the 2020 Census, accounting for 92.7% (3,108 people in the source table).
What is the full ancestry breakdown?
Colgan appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.7%), Hispanic (3.3%), Two or More Races (2.5%). 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 Colgan (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 Colgan mean?
An Irish surname derived from the Gaelic "Ó Collagáin," meaning "descendant of Collagán," a personal name of uncertain origin. 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 Colgan (1.12 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 share the surname Colgan?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.