Hennessey
Derived from an Irish surname of uncertain origin, potentially related to words meaning "descendant" or "great-grandson".
Name Census estimates that about 378 living Americans carry the first name Hennessey. The name is used almost exclusively for girls. The average person named Hennessey today is around 17 years old, and the year with the single highest number of Hennessey births was 2015 (27 babies).
This page is the full Name Census profile for Hennessey. Below you will find a gender breakdown showing how the name splits between male and female registrations, a year-by-year popularity chart stretching back to 1880, decade-level totals, the top US states for this name, its meaning and etymology, and a set of frequently asked questions with data-backed answers.
For a British comparison, Name Census UK has a UK baby-name profile for Hennessey with official rankings and popularity over time.
People living today
378
~ 1 in 906,758 Americans
Peak year
2015
27 babies that year
Average age
17
years old
2024 SSA rank
#16,129
Tracked since 1992
Census
Hennessey in the 2020 Census
The 2020 Census recorded 355 people with the first name Hennessey, which placed it at #26,287 in the published first-name tables. This is a snapshot of people who already had the name at the time of the Census.
The SSA sections elsewhere on this page answer a different question: how often parents gave the name to babies over time. The "people living today" figure on this page is different again: it is a current estimate built from SSA birth records and age-based survival rates, so the two numbers are not expected to match exactly.
2020 Census rank
#26,287
National first-name rank
People counted
355
355 in the published race/origin table
Per 100,000
0.1
People with this name in 2020
Largest reported group
Hispanic or Latino
47.3% of people with this name
Demographics
Ancestry and ethnicity for Hennessey
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Hennessey is Hispanic at 47.3%. The next largest groups are White (30.4%) and Black (13.8%). These figures describe the people who had the name in 2020, not any inherent property of the name itself.
The bar chart below shows how people with the first name Hennessey 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 name, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown so the breakdown is easy to read across every published category. Because the 2020 Census first-name file also includes raw headcounts for each group, Name Census can show those alongside the percentages in the legend and hover tooltip.
Keep in mind that these are self-reported numbers. A first name does not determine a person's race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the name Hennessey at the time of the 2020 Census, not any inherent property of the name itself.
- Hispanic or Latino47.3% · 168
- White30.4% · 108
- Black or African American13.8% · 49
- Two or more races5.4% · 19
- Asian and Pacific Islander2.0% · 7
- American Indian and Alaska Native1.1% · 4
Popularity
Hennessey: popularity over time
The SSA tracks Hennessey from the 1990s through to the 2020s, spanning 4 decades of birth certificate data. The biggest single decade for the name was the 2000s, with 153 total registrations. Although the numbers have come down from the 2000s peak, Hennessey remains solidly in use and shows no sign of disappearing from maternity wards.
Babies born per year
Decades
Hennessey by decade
The table below breaks the full SSA timeline into ten-year windows. Each row shows how many male and female babies were given the name Hennessey during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
Geography
Where Hennesseys live
Origin
Meaning and history of Hennessey
The name Hennessey is of Irish origin, deriving from the Irish Gaelic surname Ó hAnnaisí, which means "descendant of Annas". The name is believed to have originated in the early medieval period, around the 9th or 10th century AD, when Irish surnames first began to be adopted and passed down through families.
The name Annas itself is thought to be a Gaelic form of the Hebrew name Hananiah, meaning "favored by God" or "God is gracious". This Hebrew name appears in the Old Testament, particularly in the Book of Daniel, where it is the name of one of Daniel's companions in Babylonian captivity.
One of the earliest recorded bearers of the Hennessey name was Domhnall Ó hAnnaisí, a 12th-century Irish poet and historian from County Galway. In the 16th century, the name is found in the Annals of the Four Masters, a chronicle of medieval Irish history, where a Conchobhar Ó hAnnaisí is mentioned as a chief of his clan.
In the 17th century, the Hennessey family played a prominent role in the Irish Confederate Wars, with Rory Hennessey (c. 1600-1660) serving as a colonel in the Irish Confederate army. Another notable figure was Richard Hennessy (c. 1724-1800), the founder of the renowned Hennessy cognac distillery in France.
During the 19th century, several individuals with the name Hennessey gained recognition in various fields. John Hennessey (1834-1890) was an Irish-American politician and businessman who served as a member of the United States House of Representatives from Missouri. John Fitzhenry Hennessey (1861-1927) was an Australian politician and judge who served as the 21st Premier of Tasmania.
In more recent times, one of the most famous bearers of the name was the American actor and comedian John Belushi (1949-1982), whose full name was John Adam Hennessey Belushi. Other notable Hennesseys include the American football coach David Hennessey (born 1957) and the English footballer Neil Hennessey (born 1973).
People
Hennessey + last name combinations
How many people share a full name with Hennessey as the first name? Click a combination below to see the estimate, or search any pairing.
Related
Other names starting with H
Other first names starting with H with a similar number of bearers.
FAQ
Hennessey: questions and answers
How many people in the U.S. are named Hennessey?
Name Census puts the figure at roughly 378 living Americans. We arrive at this by taking every SSA birth registration for Hennessey going back to 1880 and adjusting each cohort for expected survival using CDC actuarial life tables. The result is an age-weighted living-bearer count, not a raw birth total. That works out to about 1 in 906,758 US residents.
Is Hennessey a common name?
We classify Hennessey as "Very Rare". It ranks above 81.7% of all first names in the SSA dataset by living bearers. Across the full history of the data, 383 babies have been registered with this name.
When was Hennessey most popular?
The single biggest year for Hennessey was 2015, when 27 babies received the name. The fact that the average living Hennessey is about 17 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
How common was Hennessey in the 2020 Census?
The published 2020 Census first-name tables recorded 355 people with the name Hennessey, or 0.12 per 100,000 residents. That placed it at #26,287 in the national Census ranking for first names.
Why is the Census count different from the living estimate?
Because they measure different things. The Census figure is a count of people who had the name Hennessey in 2020. The living estimate aims to answer a current question instead: how many people with the name are alive today, based on SSA birth records and age-based survival rates. Since one number is a 2020 snapshot and the other is a present-day estimate, they are not expected to be identical.
What does the Census say about the gender split for Hennessey?
In the 2020 Census sex table, Hennessey leans strongly female. 310 people counted with this name were female (86.6%), compared with 48 male bearers (13.4%). The Census view is a snapshot of people living with the name in 2020, while the SSA section above tracks births across time.
What does the Census say about the background of people named Hennessey?
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Hennessey is Hispanic at 47.3%. The next largest groups are White (30.4%) and Black (13.8%). These figures describe the people who had the name in 2020, not any inherent property of the name itself. The percentages in the chart above come from self-reported race and Hispanic-origin responses in the 2020 Census.
Which group reports the name Hennessey most often in the Census?
Hispanic is the largest reported group for people named Hennessey in the 2020 Census, accounting for 47.3% (168 people in the published table).
Why can the Census sex total and race total differ slightly?
The Census Bureau published separate 2020 tables for sex and for race/Hispanic origin, and the released figures can differ slightly because of privacy protection in the public files. That is why this page treats the gender section and the race/origin section as two related snapshots instead of forcing them into one identical total.
Does every first name have Census demographic data?
No. The public Census first-name release only includes names that met the Bureau's publication rules, so many rarer names in the SSA files have no Census demographic snapshot. When that happens, the SSA trend, gender history, and state sections still appear, but the 2020 Census demographic sections are omitted.
What does the SSA popularity chart show?
The chart tracks births, not the number of people alive with the name today. Each point shows how many babies were given the name Hennessey in that year. That makes it useful for spotting when the name rose, peaked, or faded.
Is Hennessey a female name?
Yes, 100.0% of people registered as Hennessey in the SSA data are female. You can see the full per-sex comparison in the gender distribution section above, which includes the latest year rank, birth count, and peak year for each sex.
Is Hennessey still being used today?
Yes. The SSA still recorded Hennessey in 2024, and the page above shows its latest-year rank where available. A name can be well past its peak and still remain in steady use, especially if it built up a large population over earlier decades.
Why can a name have a lot of living bearers even if it is not trendy now?
Because living-bearer counts and current baby-name popularity measure different things. A name like Hennessey can build up a very large population over many decades, even if fewer parents are choosing it now than they did at its peak.
Where does this data come from?
First-name figures come from the Social Security Administration's national baby name files, which cover every name on a birth certificate from 1880 to 2024. Living-bearer estimates layer in CDC actuarial life tables broken out by sex to account for mortality. The population baseline (342,754,338) is the Census Bureau's latest national estimate. You can read the full calculation on our methodology page.
How many people share the name Hennessey?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.