2000
#6,688
National surname rank
Recorded bearers 4,657
First available Census row
Per 100,000 1.73
Rare Last name
Thach
A Vietnamese surname derived from the Chinese surname Shi, meaning "stone" or "rock."
According to the 2020 US Census Bureau surname tables, roughly 7,861 Americans carry the last name Thach. That puts it at #4,964 in the national surname ranking, appearing at a frequency of 2.29 per 100,000 people (about 1 in 43,602 residents).
This page is the full Name Census profile for the Thach 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
7.9K
1 in 43,602
Census rank
#4,964
2020 decennial data
Per 100,000
2.3
Frequency rate
Recorded bearers
6.9K
rare in the US
Popularity narrative
The Census Bureau recorded 6,855 bearers of the surname Thach in its 2020 decennial surname file. At a rate of 2.29 per 100,000 residents, it holds the 4964th position in the national surname ranking.
Among Census respondents with the surname Thach, the largest self-reported group is Asian/Pacific Islander at 88.4%. The next largest groups are White (5.0%) and Two or More Races (3.9%).
Origin
Meaning and origin of Thach
The surname Thach is believed to have originated from Vietnam, and can be traced back to the 16th century. It is thought to have derived from the Vietnamese word "thạch," which means "stone" or "rock." This suggests that the name may have been given to individuals who lived near or worked with stone or rock formations.
In Vietnam, the name Thach was particularly prevalent in the northern regions, such as the provinces of Bac Ninh and Hung Yen. Some early records from these areas mention individuals with the surname Thach, though the exact dates are uncertain.
One of the earliest known references to the name Thach can be found in the "Dai Viet Su Ky Toan Thu," a historical text compiled during the Tran Dynasty (1225-1400). This text mentions a prominent figure named Thach Phu, who served as a military commander in the 13th century.
Another notable individual with the surname Thach was Thach Cau, a Vietnamese poet and scholar who lived during the 17th century. He was renowned for his contributions to the literature and culture of the Nguyen Dynasty (1802-1945).
In the 19th century, a man named Thach Xuan Tinh (1827-1892) gained recognition as a renowned scholar and educator. He established several schools and made significant contributions to the education system in Vietnam.
One of the most famous individuals with the surname Thach was Thach Phuong, a Vietnamese revolutionary who played a crucial role in the struggle for independence against French colonial rule in the early 20th century.
Another notable figure was Thach Thi Sang (1927-2018), a Vietnamese artist and painter who was celebrated for her depictions of traditional Vietnamese life and culture. Her works are highly regarded and can be found in various museums and galleries around the world.
While the surname Thach may have originated in Vietnam, it has since spread to other parts of the world due to migration and diaspora communities. However, its historical roots and significance remain closely tied to Vietnamese culture and history.
Demographics
Ancestry and ethnicity for Thach
Among Census respondents with the surname Thach, the largest self-reported group is Asian/Pacific Islander at 88.4%. The next largest groups are White (5.0%) and Two or More Races (3.9%).
The bar chart below shows how Thach 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 Thach surname at the time of the 2020 Census, not any inherent property of the name itself.
- Asian and Pacific Islander88.4% · 6,059
- White5.0% · 346
- Two or more races3.9% · 270
- Hispanic or Latino1.8% · 121
- Black or African American0.8% · 54
- American Indian and Alaska Native0.1% · 5
Timeline
Historical Census data for Thach
Thach 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
#5,578
National surname rank
Recorded bearers 6,229
+1,572 bearers (+33.8%)
Per 100,000 2.11
Rank movement Up 1,110 places
2020
#4,964
National surname rank
Recorded bearers 6,855
+626 bearers (+10.0%)
Per 100,000 2.29
Rank movement Up 614 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #6,688 | 4,657 | 1.73 | First available Census row | First available Census row |
| 2010 | #5,578 | 6,229 | 2.11 | +1,572 bearers (+33.8%) | Up 1,110 places |
| 2020 | #4,964 | 6,855 | 2.29 | +626 bearers (+10.0%) | Up 614 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 Thach 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 | #5,578 | #4,964 | 11.0% |
| Count | 6,229 | 6,855 | 10.0% |
| Per 100K | 2.11 | 2.29 | 8.7% |
Between the 2010 and 2020 Census, the number of Thach bearers went from 6,229 to 6,855 (+10.0% change). The surname moved up 614 positions in the national ranking, going from #5,578 to #4,964.
FAQ
Thach surname: questions and answers
How many people in the U.S. have the surname Thach?
Name Census estimates that about 7,861 living Americans carry the surname Thach. Using the current population baseline, that works out to roughly 1 in 43,602 residents.
How common is Thach?
Thach ranks #4,964 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 2.29 per 100,000 residents, which is about 2 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 6,855 people with the surname Thach. That is different from the site's living-bearer estimate (7,861), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 2.29 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 2.29 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 2 of them to have the surname Thach.
Has Thach become more or less common over time?
Between 2010 and 2020, the surname Thach went from 6,229 recorded bearers to 6,855. That is an increase of 626 (+10.0%). In the national ranking it rose from #5,578 to #4,964.
What does the Census say about the background of Thach?
Among Census respondents with the surname Thach, the largest self-reported group is Asian/Pacific Islander at 88.4%. The next largest groups are White (5.0%) and Two or More Races (3.9%). 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?
Asian/Pacific Islander is the largest self-reported group for the surname Thach in the 2020 Census, accounting for 88.4% (6,059 people in the source table).
What is the full ancestry breakdown?
Thach appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Asian/Pacific Islander (88.4%), White (5.0%), Two or More Races (3.9%). 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 Thach (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 Thach mean?
A Vietnamese surname derived from the Chinese surname Shi, meaning "stone" or "rock." 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 Thach (2.29 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 Thach?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.