How Many People Are Named William Sullivan?
There are approximately 1,662 people named William Sullivan living in the United States today. That makes this name combination common, occurring at a rate of about 1 in 206,230 Americans.
This estimate combines SSA birth records for the first name William with Census Bureau frequency data for the surname Sullivan. Below you will find a breakdown of both names, including popularity trends, gender data, and Census background data where it is available.
Estimated People with This Name
1,662
1 in 206,230 Americans
Combination Rarity
Common
First Name
View full profileWilliam
Last Name
View full profileSullivan
William: Popularity Over Time
Year-by-year SSA birth registrations for the first name William. The peak year was 1947 with 67,155 births. The average person named William today is 54 years old.
Ancestry of the First Name William
In the 2020 Census, the first name William was most commonly recorded among people who identified as White (83.31%). The next largest recorded groups were Black (6.87%) and Hispanic (5.13%).
These percentages describe the people who had the first name William in the 2020 Census. They do not tell you the deeper origin or meaning of the name itself.
Read this as a snapshot of who already had the name in 2020, not as a trend line. The SSA chart above is still the better way to see how William rose or fell over time.
Ancestry of the Sullivan Surname
The surname Sullivan was most commonly recorded among people who identified as White in the 2020 Census.
This is a self-reported race and ethnicity breakdown for people who had the surname Sullivan in the published Census surname tables. It gives useful context around who was recorded with the name, but it does not tell the full family history of every Boone line.
How we calculated this
The first name "William" has an estimated frequency of 0.681% among living Americans, based on SSA birth records from 1880 to 2024 adjusted for mortality using CDC 2023 life tables.
The surname "Sullivan" appears at a rate of 71.16 per 100,000 people in the 2020 U.S. Census.
We do not use the Census first-name snapshot for the main estimate because it is only published once every 10 years. The latest public first-name Census file is from 2020, which is already 6 years old. SSA birth records plus CDC survival data give a better current estimate of how many people with the first name William are likely to be alive now.
Multiplying these frequencies against the U.S. population of ~343 million gives 1,662 estimated people. This assumes first names and last names are statistically independent. Full methodology.
Other people named William
Other people with the surname Sullivan
William Sullivan: Questions and Answers
How many people are named William Sullivan?
We estimate approximately 1,662 people named William Sullivan are alive in the United States today. The first name William is shared by 2,335,115 Americans, and the surname Sullivan is shared by 243,910.
How rare is the name William Sullivan?
This name combination is classified as Common, occurring at a rate of about 1 in 206,230 Americans. The first name William is very common and the surname Sullivan is common.
Is William a male or female name?
William is predominantly male, with 99.6% of bearers being male and 0.4% female. It peaked in popularity in 1947 and the average bearer today is 54 years old.
What does the Census say about the first name William?
In the 2020 Census, the first name William was most commonly recorded among people who identified as White (83.31%). The next largest recorded groups were Black (6.87%) and Hispanic (5.13%). These percentages describe the people who had the name in the 2020 Census, not the deeper origin of the name itself.
Where does this data come from?
First name data comes from the Social Security Administration (1880 to 2024), adjusted for survival using CDC 2023 life tables. When available, first-name Census background data comes from the 2020 U.S. Census Bureau first-name tables. Surname data comes from the 2020 U.S. Census Bureau. Full methodology.
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