2000
#127,186
National surname rank
Recorded bearers 124
First available Census row
Per 100,000 0.05
Very Rare Last name
Trethaway
A Cornish surname thought to mean someone from the district of Trethaway.
According to the 2020 US Census Bureau surname tables, roughly 116 Americans carry the last name Trethaway. That puts it at #155,270 in the national surname ranking, appearing at a frequency of 0.03 per 100,000 people (about 1 in 2,954,779 residents).
This page is the full Name Census profile for the Trethaway 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
116
1 in 2,954,779
Census rank
#155,270
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
101
very rare in the US
Popularity narrative
The Census Bureau recorded 101 bearers of the surname Trethaway in its 2020 decennial surname file. At a rate of 0.03 per 100,000 residents, it holds the 155270th position in the national surname ranking.
Among Census respondents with the surname Trethaway, the largest self-reported group is White at 85.1%. The next largest groups are Two or More Races (7.9%) and Hispanic (5.9%).
Origin
Meaning and origin of Trethaway
The surname Trethaway is believed to have originated in Cornwall, England during the medieval period. It is derived from the Cornish word "tre," meaning a farmstead or hamlet, and "theway," which was likely a personal name or a topographical feature reference. This suggests that the name was initially assigned to someone who lived at or near a particular farmstead associated with the individual known as Theway.
The earliest known record of the Trethaway name appears in the Assize Rolls of Cornwall from 1284, where a certain Robertus de Trethawey is mentioned. This indicates that variations of the spelling, such as Trethawey, were in use during this era. The name may also have connections to the Cornish place name Trethewey, which is a small village near Bodmin.
In the 16th century, the Trethaway surname is found in various records across Cornwall. John Trethaway, born around 1520, is documented as being from the parish of Probus. Another notable figure was Richard Trethaway, a prominent merchant and landowner from St. Columb Major, who lived from approximately 1560 to 1632.
The Domesday Book, compiled in 1086, does not appear to contain any direct references to the Trethaway name, likely due to its relatively late emergence in the medieval period. However, the book does mention several place names in Cornwall that may have influenced the formation of the surname over time.
During the 17th and 18th centuries, several individuals with the Trethaway surname gained recognition. One such person was Thomas Trethaway, a renowned painter and engraver born in Cornwall in 1676. His works were widely celebrated during his lifetime and can be found in various art collections.
Another notable figure was William Trethaway, a prominent churchman and scholar who lived from 1698 to 1784. He served as the Archdeacon of Cornwall and was highly regarded for his contributions to religious studies and local history.
In the 19th century, the Trethaway name continued to be associated with Cornwall. One example is John Trethaway, a celebrated poet and writer born in 1812 in Penzance. His works, which often focused on the Cornish landscape and culture, were widely published and acclaimed during the Victorian era.
While the Trethaway surname is not among the most common in Cornwall or the wider United Kingdom, it has a rich history deeply rooted in the region's medieval and early modern past. The name's enduring presence in various records and the achievements of notable individuals bearing it serve as a testament to its enduring legacy.
Demographics
Ancestry and ethnicity for Trethaway
Among Census respondents with the surname Trethaway, the largest self-reported group is White at 85.1%. The next largest groups are Two or More Races (7.9%) and Hispanic (5.9%).
The bar chart below shows how Trethaway 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 Trethaway surname at the time of the 2020 Census, not any inherent property of the name itself.
- White85.1% · 86
- Two or more races7.9% · 8
- Hispanic or Latino5.9% · 6
- American Indian and Alaska Native1.0% · 1
Timeline
Historical Census data for Trethaway
Trethaway 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
#128,249
National surname rank
Recorded bearers 133
+9 bearers (+7.3%)
Per 100,000 0.05
Rank movement Down 1,063 places
2020
#155,270
National surname rank
Recorded bearers 101
-32 bearers (-24.1%)
Per 100,000 0.03
Rank movement Down 27,021 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #127,186 | 124 | 0.05 | First available Census row | First available Census row |
| 2010 | #128,249 | 133 | 0.05 | +9 bearers (+7.3%) | Down 1,063 places |
| 2020 | #155,270 | 101 | 0.03 | -32 bearers (-24.1%) | Down 27,021 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 Trethaway 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 | #128,249 | #155,270 | -21.1% |
| Count | 133 | 101 | -24.1% |
| Per 100K | 0.05 | 0.03 | -32.4% |
Between the 2010 and 2020 Census, the number of Trethaway bearers went from 133 to 101 (-24.1% change). The surname moved down 27,021 positions in the national ranking, going from #128,249 to #155,270.
FAQ
Trethaway surname: questions and answers
How many people in the U.S. have the surname Trethaway?
Name Census estimates that about 116 living Americans carry the surname Trethaway. Using the current population baseline, that works out to roughly 1 in 2,954,779 residents.
How common is Trethaway?
Trethaway ranks #155,270 in the 2020 Census surname tables and is classified on this site as "Very Rare." The Census recorded the name at a frequency of 0.03 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 101 people with the surname Trethaway. That is different from the site's living-bearer estimate (116), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 0.03 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 0.03 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 Trethaway.
Has Trethaway become more or less common over time?
Between 2010 and 2020, the surname Trethaway went from 133 recorded bearers to 101. That is a decrease of 32 (-24.1%). In the national ranking it fell from #128,249 to #155,270.
What does the Census say about the background of Trethaway?
Among Census respondents with the surname Trethaway, the largest self-reported group is White at 85.1%. The next largest groups are Two or More Races (7.9%) and Hispanic (5.9%). 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 Trethaway in the 2020 Census, accounting for 85.1% (86 people in the source table).
What is the full ancestry breakdown?
Trethaway appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (85.1%), Two or More Races (7.9%), Hispanic (5.9%). 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 Trethaway (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 Trethaway mean?
A Cornish surname thought to mean someone from the district of Trethaway. 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 Trethaway (0.03 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 last name Trethaway?
Want to know how many people are called Trethaway? HowManyOfMe.org, our sister site, puts the living-bearer count front and centre.