2000
#110,523
National surname rank
Recorded bearers 148
First available Census row
Per 100,000 0.05
Very Rare Last name
Treharn
An occupational name for someone who kept the town furnace or smithy.
According to the 2020 US Census Bureau surname tables, roughly 132 Americans carry the last name Treharn. That puts it at #145,757 in the national surname ranking, appearing at a frequency of 0.04 per 100,000 people (about 1 in 2,596,624 residents).
This page is the full Name Census profile for the Treharn 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.
Bearers in the US
132
1 in 2,596,624
Census rank
#145,757
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
115
very rare in the US
Popularity narrative
The Census Bureau recorded 115 bearers of the surname Treharn in its 2020 decennial surname file. At a rate of 0.04 per 100,000 residents, it holds the 145757th position in the national surname ranking.
Among Census respondents with the surname Treharn, the largest self-reported group is White at 97.4%. The next largest groups are Two or More Races (2.6%).
Origin
Meaning and origin of Treharn
The surname Treharn is believed to have originated in Wales, tracing its roots back to the early medieval period. It is thought to be a locational name derived from the Welsh place name Tre-hearn, which translates to "the homestead on the stream." This suggests that the earliest bearers of this name likely hailed from a settlement situated near a flowing body of water.
In its earliest recorded forms, the name appeared as Treharne, Trehern, and Treharne, reflecting the variations in spelling that were common during the Middle Ages. One of the earliest known references to the name can be found in the Plea Rolls of Shropshire from 1209, where a person named Richard de Treherne is mentioned.
The Treharn surname has a long and rich history in Wales, with several notable individuals bearing this name throughout the centuries. One such figure was Rhys Treharne (c. 1540-1610), a Welsh landowner and Member of Parliament who represented Cardiganshire in the early 17th century.
Another prominent Treharn was Sir William Treharne (1586-1659), a Welsh lawyer and judge who served as the King's Sergeant-at-Law during the reign of King Charles I. His involvement in the English Civil War and his support for the Royalist cause earned him a reputation as a staunch defender of the Crown.
In the literary realm, John Treharne (1788-1863) was a Welsh writer and poet who published several works in both Welsh and English. His contributions to the preservation of Welsh culture and language earned him a place in the annals of Welsh literature.
The Treharn name also found its way into the ecclesiastical sphere, with figures like Edward Treharne (1718-1784), a Welsh Anglican priest who served as the Bishop of Llandaff and later as the Bishop of St. David's in the late 18th century.
Across the Atlantic, the Treharn surname took root in the American colonies, with records indicating the presence of individuals bearing this name as early as the 17th century. One notable example is William Treharne (1670-1741), a Welsh-born Quaker who settled in Pennsylvania and became a prominent figure in the early Quaker community.
While the Treharn surname may not be among the most common in the world today, its historical significance and deep roots in Wales and beyond serve as a testament to the rich tapestry of cultural heritage woven into the fabric of family names.
Demographics
Ancestry and ethnicity for Treharn
Among Census respondents with the surname Treharn, the largest self-reported group is White at 97.4%. The next largest groups are Two or More Races (2.6%).
The bar chart below shows how Treharn 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 Treharn surname at the time of the 2020 Census, not any inherent property of the name itself.
- White97.4% · 112
- Two or more races2.6% · 3
Timeline
Historical Census data for Treharn
Treharn 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
#127,494
National surname rank
Recorded bearers 134
-14 bearers (-9.5%)
Per 100,000 0.05
Rank movement Down 16,971 places
2020
#145,757
National surname rank
Recorded bearers 115
-19 bearers (-14.2%)
Per 100,000 0.04
Rank movement Down 18,263 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #110,523 | 148 | 0.05 | First available Census row | First available Census row |
| 2010 | #127,494 | 134 | 0.05 | -14 bearers (-9.5%) | Down 16,971 places |
| 2020 | #145,757 | 115 | 0.04 | -19 bearers (-14.2%) | Down 18,263 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 Treharn 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 | #127,494 | #145,757 | -14.3% |
| Count | 134 | 115 | -14.2% |
| Per 100K | 0.05 | 0.04 | -23.1% |
Between the 2010 and 2020 Census, the number of Treharn bearers went from 134 to 115 (-14.2% change). The surname moved down 18,263 positions in the national ranking, going from #127,494 to #145,757.
FAQ
Treharn surname: questions and answers
How many people in the U.S. have the surname Treharn?
Name Census estimates that about 132 living Americans carry the surname Treharn. Using the current population baseline, that works out to roughly 1 in 2,596,624 residents.
How common is Treharn?
Treharn ranks #145,757 in the 2020 Census surname tables and is classified on this site as "Very Rare." The Census recorded the name at a frequency of 0.04 per 100,000 residents, which is about 0 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 115 people with the surname Treharn. That is different from the site's living-bearer estimate (132), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.04 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.04 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 0 of them to have the surname Treharn.
Has Treharn become more or less common over time?
Between 2010 and 2020, the surname Treharn went from 134 recorded bearers to 115. That is a decrease of 19 (-14.2%). In the national ranking it fell from #127,494 to #145,757.
What does the Census say about the background of Treharn?
Among Census respondents with the surname Treharn, the largest self-reported group is White at 97.4%. The next largest groups are Two or More Races (2.6%). 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 Treharn in the 2020 Census, accounting for 97.4% (112 people in the source table).
What is the full ancestry breakdown?
Treharn appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (97.4%), Two or More Races (2.6%). 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 Treharn (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 Treharn mean?
An occupational name for someone who kept the town furnace or smithy. 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 Treharn (0.04 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 have the surname Treharn?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.