2000
#146,011
National surname rank
Recorded bearers 104
First available Census row
Per 100,000 0.04
Very Rare Last name
Mroczko
A surname of Polish origin meaning "something or someone dark or gloomy."
According to the 2020 US Census Bureau surname tables, roughly 130 Americans carry the last name Mroczko. That puts it at #147,221 in the national surname ranking, appearing at a frequency of 0.04 per 100,000 people (about 1 in 2,636,572 residents).
This page is the full Name Census profile for the Mroczko 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
130
1 in 2,636,572
Census rank
#147,221
2020 decennial data
Per 100,000
0.0
Frequency rate
Recorded bearers
113
very rare in the US
Popularity narrative
The Census Bureau recorded 113 bearers of the surname Mroczko in its 2020 decennial surname file. At a rate of 0.04 per 100,000 residents, it holds the 147221st position in the national surname ranking.
Among Census respondents with the surname Mroczko, the largest self-reported group is White at 92.0%. The next largest groups are Hispanic (5.3%) and Black (1.8%).
Origin
Meaning and origin of Mroczko
The surname Mroczko is of Polish origin and dates back to the late Middle Ages. It is derived from the Polish word "mrok," meaning darkness or gloom, with the diminutive suffix "-ko" added to create a surname meaning "little darkness."
This surname likely originated in the regions of present-day Poland, where it was first used to identify individuals by a descriptive nickname or a reference to their occupation or place of residence. One theory suggests that the name may have been given to someone who lived in a particularly dark or gloomy area, or perhaps worked in a profession that involved working in dimly lit conditions.
While there are no definitive historical references to the name Mroczko in early Polish records or manuscripts, its structure and linguistic roots point to its medieval origins. The earliest known recorded instances of the name are found in parish registers and census records from the 16th and 17th centuries in various regions of Poland.
Notable individuals with the surname Mroczko include Józef Mroczko (1780-1841), a Polish military officer and participant in the Kościuszko Uprising against Russian rule. Another notable bearer of the name was Józef Mroczko (1829-1912), a Polish Catholic priest and writer who published several works on religious topics.
In the 19th century, Franciszek Mroczko (1837-1885) was a Polish painter and artist known for his landscapes and genre scenes depicting rural life in Poland. Wincenty Mroczko (1844-1908) was a Polish lawyer and politician who served as a member of the Galician Sejm, the regional parliament of the Kingdom of Galicia and Lodomeria, which was part of the Austro-Hungarian Empire.
In more recent history, Tadeusz Mroczko (1921-2016) was a Polish writer, poet, and translator who published several collections of poetry and translations of works by foreign authors into Polish.
Demographics
Ancestry and ethnicity for Mroczko
Among Census respondents with the surname Mroczko, the largest self-reported group is White at 92.0%. The next largest groups are Hispanic (5.3%) and Black (1.8%).
The bar chart below shows how Mroczko 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 Mroczko surname at the time of the 2020 Census, not any inherent property of the name itself.
- White92.0% · 104
- Hispanic or Latino5.3% · 6
- Black or African American1.8% · 2
- Asian and Pacific Islander0.9% · 1
Timeline
Historical Census data for Mroczko
Mroczko 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
#159,712
National surname rank
Recorded bearers 101
-3 bearers (-2.9%)
Per 100,000 0.03
Rank movement Down 13,701 places
2020
#147,221
National surname rank
Recorded bearers 113
+12 bearers (+11.9%)
Per 100,000 0.04
Rank movement Up 12,491 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #146,011 | 104 | 0.04 | First available Census row | First available Census row |
| 2010 | #159,712 | 101 | 0.03 | -3 bearers (-2.9%) | Down 13,701 places |
| 2020 | #147,221 | 113 | 0.04 | +12 bearers (+11.9%) | Up 12,491 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 Mroczko 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 | #159,712 | #147,221 | 7.8% |
| Count | 101 | 113 | 11.9% |
| Per 100K | 0.03 | 0.04 | 26.0% |
Between the 2010 and 2020 Census, the number of Mroczko bearers went from 101 to 113 (+11.9% change). The surname moved up 12,491 positions in the national ranking, going from #159,712 to #147,221.
FAQ
Mroczko surname: questions and answers
How many people in the U.S. have the surname Mroczko?
Name Census estimates that about 130 living Americans carry the surname Mroczko. Using the current population baseline, that works out to roughly 1 in 2,636,572 residents.
How common is Mroczko?
Mroczko ranks #147,221 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 113 people with the surname Mroczko. That is different from the site's living-bearer estimate (130), 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 Mroczko.
Has Mroczko become more or less common over time?
Between 2010 and 2020, the surname Mroczko went from 101 recorded bearers to 113. That is an increase of 12 (+11.9%). In the national ranking it rose from #159,712 to #147,221.
What does the Census say about the background of Mroczko?
Among Census respondents with the surname Mroczko, the largest self-reported group is White at 92.0%. The next largest groups are Hispanic (5.3%) and Black (1.8%). 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?
White is the largest self-reported group for the surname Mroczko in the 2020 Census, accounting for 92.0% (104 people in the source table).
What is the full ancestry breakdown?
Mroczko appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (92.0%), Hispanic (5.3%), Black (1.8%). 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 Mroczko (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 Mroczko mean?
A surname of Polish origin meaning "something or someone dark or gloomy." 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 Mroczko (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 common is the surname Mroczko?
Want to know how many people have the surname Mroczko? HowManyOfMe.org, our sister site, puts the living-bearer count front and centre.