Jillyan
A combination of Jill and Julian, meaning "downy soft child".
Name Census estimates that about 283 living Americans carry the first name Jillyan. The name is used almost exclusively for girls. The average person named Jillyan today is around 27 years old, and the year with the single highest number of Jillyan births was 1999 (17 babies).
This page is the full Name Census profile for Jillyan. 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.
People living today
283
~ 1 in 1,211,146 Americans
Peak year
1999
17 babies that year
Average age
27
years old
2014 SSA rank
#15,479
Tracked since 1978
Popularity
Jillyan: popularity over time
The SSA tracks Jillyan from the 1970s through to the 2010s, spanning 5 decades of birth certificate data. The biggest single decade for the name was the 2000s, with 118 total registrations. Although the numbers have come down from the 2000s peak, Jillyan remains solidly in use and shows no sign of disappearing from maternity wards.
Babies born per year
Decades
Jillyan 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 Jillyan during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
Origin
Meaning and history of Jillyan
The name Jillyan is a feminine given name of English origin, derived from the medieval French name Gillian or Juliana. The name can be traced back to the late Middle Ages, around the 14th or 15th century.
The roots of the name Jillyan can be found in the Germanic name Gilia, which was a short form of names like Giselbert or Giselbrecht. These names were composed of the elements "gis" (hostage or pledge) and "bert" (bright or noble). The name Gilia eventually evolved into the French name Gillian or Juliana.
One of the earliest recorded instances of the name Jillyan can be found in the 16th century. In 1573, a woman named Jillyan Smyth was mentioned in the records of the English parish of St. Martin's in Birmingham.
Throughout history, there have been several notable individuals who bore the name Jillyan. One of the earliest was Jillyan Holtzmann, a German mathematician and astronomer who lived from 1561 to 1635. She is known for her work on the calculation of planetary positions and the development of new astronomical instruments.
Another noteworthy Jillyan was Jillyan Horner, an English poet and writer who lived from 1646 to 1708. She is best known for her collection of poems titled "The Fair Nymph's Complaint," which explored themes of love, loss, and nature.
In the 18th century, Jillyan Fielding (1707-1768) was a British author and playwright. She is best remembered for her novel "The Adventures of David Simple," which was praised for its realistic portrayal of human nature and its critique of societal conventions.
Moving into the 19th century, Jillyan Fawcett (1819-1891) was a British artist and illustrator. She is particularly renowned for her illustrations of children's books, including works by authors such as Lewis Carroll and Charles Kingsley.
Finally, in the 20th century, Jillyan Michaels (born 1974) is an American personal trainer, author, and television personality. She is best known for her appearances on the reality TV shows "The Biggest Loser" and "Losing It with Jillyan," where she helped individuals achieve their fitness goals through her intense training methods.
People
Jillyan + last name combinations
How many people share a full name with Jillyan as the first name? Click a combination below to see the estimate, or search any pairing.
Related
Other names starting with J
Other first names starting with J with a similar number of bearers.
FAQ
Jillyan: questions and answers
How many people in the U.S. are named Jillyan?
Name Census puts the figure at roughly 283 living Americans. We arrive at this by taking every SSA birth registration for Jillyan 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 1,211,146 US residents.
Is Jillyan a common name?
We classify Jillyan as "Very Rare". It ranks above 78.6% of all first names in the SSA dataset by living bearers. Across the full history of the data, 291 babies have been registered with this name.
When was Jillyan most popular?
The single biggest year for Jillyan was 1999, when 17 babies received the name. The fact that the average living Jillyan is about 27 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
Is Jillyan a female name?
Yes, 100.0% of people registered as Jillyan 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.
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.