How Many People Are Named Hennessey?
An estimated 378 people in the United States have the first name Hennessey. It is almost exclusively a female name. The average bearer is 17 years old, and Hennessey peaked in popularity in 2015 with 27 births that year.
Below you will find a full statistical profile of Hennessey as a first name in the United States, including gender data, a year-by-year popularity timeline going back to 1880, a decade breakdown, and state-by-state birth registrations. You can also check how many people share the full name Hennessey paired with any surname.
Estimated Living Americans
378
About 1 in 906,758 people in the U.S.
Rarity
Very Rare
Predicted Gender
Female
100.0% confidence
Average Age
17
years old
Peak Year
2015
27 births
Total Registered
383
since 1880
Gender Distribution for Hennessey
Hennessey is almost exclusively a female name. Out of 383 total births registered, 100.0% were female.
Hennessey as a female name
Ranked #16,129 in 2024
5 female births in 2024
Peak: 2015 (27 births)
Hennessey: Popularity Over Time
SSA records for Hennessey span from the 1990s to the 2020s, covering 4 decades of naming data. The most popular decade for this name was the 2000s, when 153 babies were registered. While Hennessey is less common than at its peak in the 2000s, it remains a well-established name with steady registrations.
Hennessey by Decade
How has Hennessey tracked across different eras? The table below groups all SSA birth registrations into 10-year periods, with separate male and female counts. The colored bar shows each decade's share relative to the peak.
Hennessey by State
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.
Names Similar to Hennessey
Other first names starting with H with a similar number of bearers.
Hennessey: Questions and Answers
How many people in the U.S. are named Hennessey?
We estimate approximately 378 people named Hennessey are alive in the United States today. This is based on SSA birth records from 1880 to 2024, adjusted for mortality using CDC life tables. About 1 in 906,758 Americans share this first name.
Is Hennessey a common name?
Hennessey is classified as "Very Rare" and is more popular than 81.7% of all first names in the SSA database. A total of 383 births have been registered with this name since 1880.
When was Hennessey most popular?
Hennessey reached peak popularity in 2015, when 27 babies were given this name. The average age of a living person named Hennessey is approximately 17 years old, reflecting when the name was most commonly given.
Is Hennessey a female name?
Hennessey is predominantly female. 100.0% of people with this name are female. See the gender breakdown above for full details.
How many Hennessey Smiths are there?
To find how many people share a specific full name, we combine first name and surname frequencies. Try: Hennessey Smith, Hennessey Johnson, Hennessey Williams. You can also search any combination on our homepage.
Where does this data come from?
Our estimates use Social Security Administration birth records (1880 to 2024), adjusted for survival using CDC 2023 life tables broken down by sex. The U.S. population figure (342,754,338) is from the Census Bureau's July 2025 estimate. Full methodology.
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