2000
#4,563
National surname rank
Recorded bearers 7,134
First available Census row
Per 100,000 2.64
Rare Last name
Mosby
Derived from the Old English place name Moresby, meaning "farmstead or village by the moor or marshland."
According to the 2020 US Census Bureau surname tables, roughly 8,372 Americans carry the last name Mosby. That puts it at #4,707 in the national surname ranking, appearing at a frequency of 2.44 per 100,000 people (about 1 in 40,941 residents).
This page is the full Name Census profile for the Mosby 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 Mosby with 1881 census detail, origin facts and modern UK distribution where available.
Bearers in the US
8.4K
1 in 40,941
Census rank
#4,707
2020 decennial data
Per 100,000
2.4
Frequency rate
Recorded bearers
7.3K
rare in the US
Popularity narrative
The Census Bureau recorded 7,301 bearers of the surname Mosby in its 2020 decennial surname file. At a rate of 2.44 per 100,000 residents, it holds the 4707th position in the national surname ranking.
Among Census respondents with the surname Mosby, the largest self-reported group is Black at 62.2%. The next largest groups are White (28.3%) and Two or More Races (5.8%).
Origin
Meaning and origin of Mosby
The surname Mosby is of English origin and is believed to have originated in the county of Leicestershire, England, during the late medieval period. It is thought to be derived from the Old Norse byname "Musse," which means "little mouse," and the Old English word "by," meaning a town or village. This suggests that the name may have been given to someone who lived near a small settlement or hamlet.
One of the earliest records of the name Mosby can be found in the Hundredorum Rolls of 1273, which mentions a William de Mussebi. This indicates that the name was already in use by the 13th century. The Subsidy Rolls of Leicestershire from 1327 also contain references to individuals with the surname Mosby or similar spellings, such as Robert de Mussebury and John de Mussebury.
In the 15th century, the name appeared in various historical documents, including the Paston Letters, which were a collection of correspondence between members of the Paston family in Norfolk. One letter, dated 1472, mentions a Sir John Mosby.
The earliest known person with the surname Mosby was likely Sir John Mosby, who lived in the late 14th and early 15th centuries. He was a prominent landowner and knight in Leicestershire and is mentioned in several legal records from the time.
Another notable individual with the Mosby surname was Sir Nicholas Mosby, who was born around 1505 and served as the High Sheriff of Leicestershire in 1557. He was a wealthy landowner and played a role in local politics during the Tudor period.
In the 17th century, one of the most famous bearers of the Mosby name was John Mosby, a British soldier and politician who lived from 1629 to 1688. He served as a Colonel in the English Civil War and later became a Member of Parliament.
During the American Civil War, the Confederate cavalry officer John Singleton Mosby, also known as the "Gray Ghost," gained notoriety for his daring raids behind Union lines. He was born in 1833 and died in 1916.
Another noteworthy individual with the Mosby surname was Walter Mosby, an English actor and playwright who lived from 1672 to 1739. He was known for his roles in Shakespearean plays and his own theatrical works.
Demographics
Ancestry and ethnicity for Mosby
Among Census respondents with the surname Mosby, the largest self-reported group is Black at 62.2%. The next largest groups are White (28.3%) and Two or More Races (5.8%).
The bar chart below shows how Mosby 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 Mosby surname at the time of the 2020 Census, not any inherent property of the name itself.
- Black or African American62.2% · 4,540
- White28.3% · 2,068
- Two or more races5.8% · 426
- Hispanic or Latino2.8% · 203
- American Indian and Alaska Native0.5% · 36
- Asian and Pacific Islander0.4% · 28
Timeline
Historical Census data for Mosby
Mosby 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
#4,699
National surname rank
Recorded bearers 7,549
+415 bearers (+5.8%)
Per 100,000 2.56
Rank movement Down 136 places
2020
#4,707
National surname rank
Recorded bearers 7,301
-248 bearers (-3.3%)
Per 100,000 2.44
Rank movement Down 8 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #4,563 | 7,134 | 2.64 | First available Census row | First available Census row |
| 2010 | #4,699 | 7,549 | 2.56 | +415 bearers (+5.8%) | Down 136 places |
| 2020 | #4,707 | 7,301 | 2.44 | -248 bearers (-3.3%) | Down 8 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 Mosby 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 | #4,699 | #4,707 | -0.2% |
| Count | 7,549 | 7,301 | -3.3% |
| Per 100K | 2.56 | 2.44 | -4.6% |
Between the 2010 and 2020 Census, the number of Mosby bearers went from 7,549 to 7,301 (-3.3% change). The surname moved down 8 positions in the national ranking, going from #4,699 to #4,707.
FAQ
Mosby surname: questions and answers
How many people in the U.S. have the surname Mosby?
Name Census estimates that about 8,372 living Americans carry the surname Mosby. Using the current population baseline, that works out to roughly 1 in 40,941 residents.
How common is Mosby?
Mosby ranks #4,707 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 2.44 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 7,301 people with the surname Mosby. That is different from the site's living-bearer estimate (8,372), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 2.44 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 2.44 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 Mosby.
Has Mosby become more or less common over time?
Between 2010 and 2020, the surname Mosby went from 7,549 recorded bearers to 7,301. That is a decrease of 248 (-3.3%). In the national ranking it fell from #4,699 to #4,707.
What does the Census say about the background of Mosby?
Among Census respondents with the surname Mosby, the largest self-reported group is Black at 62.2%. The next largest groups are White (28.3%) and Two or More Races (5.8%). 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?
Black is the largest self-reported group for the surname Mosby in the 2020 Census, accounting for 62.2% (4,540 people in the source table).
What is the full ancestry breakdown?
Mosby appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are Black (62.2%), White (28.3%), Two or More Races (5.8%). 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 Mosby (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 Mosby mean?
Derived from the Old English place name Moresby, meaning "farmstead or village by the moor or marshland." 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 Mosby (2.44 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 Americans have the surname Mosby?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.