2000
#7,457
National surname rank
Recorded bearers 4,116
First available Census row
Per 100,000 1.53
Rare Last name
Mortenson
A patronymic surname derived from the personal name Morten, meaning "son of Morten."
According to the 2020 US Census Bureau surname tables, roughly 4,652 Americans carry the last name Mortenson. That puts it at #7,842 in the national surname ranking, appearing at a frequency of 1.36 per 100,000 people (about 1 in 73,679 residents).
This page is the full Name Census profile for the Mortenson 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
4.7K
1 in 73,679
Census rank
#7,842
2020 decennial data
Per 100,000
1.4
Frequency rate
Recorded bearers
4.1K
rare in the US
Popularity narrative
The Census Bureau recorded 4,057 bearers of the surname Mortenson in its 2020 decennial surname file. At a rate of 1.36 per 100,000 residents, it holds the 7842nd position in the national surname ranking.
Among Census respondents with the surname Mortenson, the largest self-reported group is White at 91.7%. The next largest groups are Hispanic (3.8%) and Two or More Races (2.7%).
Origin
Meaning and origin of Mortenson
The surname Mortenson originated in Scandinavia, specifically in the regions of Norway and Sweden. Its roots can be traced back to the Old Norse language, where it was derived from the combination of the words "mor" meaning "moor" or "marsh" and "tun" meaning "farm" or "homestead." This suggests that the name may have initially referred to people who lived on or near a marshy or swampy area.
In its earliest known forms, the name was spelled as "Mortunsson" or "Mortunsen" in Norway and Sweden. It is believed to have emerged as a patronymic surname, denoting the son of someone named Mortun or a variant thereof.
One of the earliest recorded instances of the name can be found in the Diplomatarium Norvegicum, a collection of Norwegian medieval documents dating back to the 13th century. Here, the name appeared as "Mortunsson" in a document from the year 1279.
As the name spread across Scandinavia and eventually to other parts of Europe, it underwent various spelling variations, such as "Mortensen," "Mortinson," and "Mortenson." These changes were often influenced by local dialects and linguistic adaptations.
Among notable historical figures bearing the Mortenson surname, one can mention:
1. Anders Mortenson (1678-1741), a Norwegian farmer and landowner who played a significant role in the early settlement of the Telemark region in Norway.
2. Johan Mortenson (1811-1893), a Swedish-born American pioneer and farmer who was among the first settlers in the Red River Valley of Minnesota.
3. Olaf Mortenson (1857-1935), a Norwegian-American architect known for designing numerous churches and public buildings in the Pacific Northwest region of the United States.
4. Ingrid Mortenson (1904-1988), a Swedish painter and sculptor whose works were heavily influenced by the Scandinavian modernist movement.
5. Lars Mortenson (born 1957), a Danish historian and author who has written extensively on the Viking Age and the early medieval period in Scandinavia.
As the name spread across continents due to migration and exploration, it continued to evolve and adapt to local linguistic and cultural influences, reflecting the rich tapestry of human history and the diverse paths taken by those who carried this surname.
Demographics
Ancestry and ethnicity for Mortenson
Among Census respondents with the surname Mortenson, the largest self-reported group is White at 91.7%. The next largest groups are Hispanic (3.8%) and Two or More Races (2.7%).
The bar chart below shows how Mortenson 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 Mortenson surname at the time of the 2020 Census, not any inherent property of the name itself.
- White91.7% · 3,719
- Hispanic or Latino3.8% · 156
- Two or more races2.7% · 110
- American Indian and Alaska Native0.7% · 28
- Asian and Pacific Islander0.6% · 25
- Black or African American0.5% · 19
Timeline
Historical Census data for Mortenson
Mortenson 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
#7,710
National surname rank
Recorded bearers 4,306
+190 bearers (+4.6%)
Per 100,000 1.46
Rank movement Down 253 places
2020
#7,842
National surname rank
Recorded bearers 4,057
-249 bearers (-5.8%)
Per 100,000 1.36
Rank movement Down 132 places
| Year | Rank | Count | Per 100K | Count change | Rank change |
|---|---|---|---|---|---|
| 2000 | #7,457 | 4,116 | 1.53 | First available Census row | First available Census row |
| 2010 | #7,710 | 4,306 | 1.46 | +190 bearers (+4.6%) | Down 253 places |
| 2020 | #7,842 | 4,057 | 1.36 | -249 bearers (-5.8%) | Down 132 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 Mortenson 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 | #7,710 | #7,842 | -1.7% |
| Count | 4,306 | 4,057 | -5.8% |
| Per 100K | 1.46 | 1.36 | -7.0% |
Between the 2010 and 2020 Census, the number of Mortenson bearers went from 4,306 to 4,057 (-5.8% change). The surname moved down 132 positions in the national ranking, going from #7,710 to #7,842.
FAQ
Mortenson surname: questions and answers
How many people in the U.S. have the surname Mortenson?
Name Census estimates that about 4,652 living Americans carry the surname Mortenson. Using the current population baseline, that works out to roughly 1 in 73,679 residents.
How common is Mortenson?
Mortenson ranks #7,842 in the 2020 Census surname tables and is classified on this site as "Rare." The Census recorded the name at a frequency of 1.36 per 100,000 residents, which is about 1 people out of every 100,000.
How many people with this surname were counted in the Census?
The raw 2020 Census file counted 4,057 people with the surname Mortenson. That is different from the site's living-bearer estimate (4,652), which projects the surname's present-day count by applying the Census frequency rate to the current U.S. population.
What does 1.36 per 100,000 actually mean?
It is the Census Bureau's normalized frequency measure. A rate of 1.36 per 100,000 means that if you picked a random group of 100,000 U.S. residents, you would expect about 1 of them to have the surname Mortenson.
Has Mortenson become more or less common over time?
Between 2010 and 2020, the surname Mortenson went from 4,306 recorded bearers to 4,057. That is a decrease of 249 (-5.8%). In the national ranking it fell from #7,710 to #7,842.
What does the Census say about the background of Mortenson?
Among Census respondents with the surname Mortenson, the largest self-reported group is White at 91.7%. The next largest groups are Hispanic (3.8%) and Two or More Races (2.7%). 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 Mortenson in the 2020 Census, accounting for 91.7% (3,719 people in the source table).
What is the full ancestry breakdown?
Mortenson appears across multiple self-reported groups in the Census data. The largest shares in the 2020 file are White (91.7%), Hispanic (3.8%), Two or More Races (2.7%). 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 Mortenson (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 Mortenson mean?
A patronymic surname derived from the personal name Morten, meaning "son of Morten." 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 Mortenson (1.36 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 Mortenson?
You can see how many people are called Mortenson on our sister site HowManyOfMe.org — same data roots, lighter UI.