Jilliam
Combination of the names Jill and William.
Name Census estimates that about 97 living Americans carry the first name Jilliam. The name is used almost exclusively for girls. The average person named Jilliam today is around 39 years old, and the year with the single highest number of Jilliam births was 1987 (15 babies).
This page is the full Name Census profile for Jilliam. 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.
Key insights
- • Fewer than 100 living Americans are believed to carry the name Jilliam. It is among the rarest names in the SSA records.
People living today
97
~ 1 in 3,533,550 Americans
Peak year
1987
15 babies that year
Average age
39
years old
1993 SSA rank
#14,447
Tracked since 1982
Popularity
Jilliam: popularity over time
The SSA tracks Jilliam from the 1980s through to the 1990s, spanning 2 decades of birth certificate data. The biggest single decade for the name was the 1980s, with 72 total registrations. Although the numbers have come down from the 1980s peak, Jilliam remains solidly in use and shows no sign of disappearing from maternity wards.
Babies born per year
Decades
Jilliam 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 Jilliam 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 Jilliam
The given name Jilliam has its roots in the Old English language, originating during the medieval period around the 9th century. It is believed to be a combination of two distinct words: "gild" meaning "pledge" or "payment," and "helm" which translates to "helmet" or "protection." The name's original meaning likely referred to someone who provided security or safeguarded valuables in exchange for compensation.
One of the earliest recorded instances of the name Jilliam can be found in the Domesday Book, a comprehensive survey of landholdings and property ownership commissioned by William the Conqueror in 1086. The entry mentions a certain "Jilliam the Steward," who oversaw the management of estates in the county of Wiltshire.
In the 12th century, a prominent figure named Jilliam of Malmesbury gained recognition as a renowned English historian and scholar. His most notable work, "Gesta Regum Anglorum" (Deeds of the English Kings), chronicled the history of England from the arrival of the Anglo-Saxons to the year 1126.
During the 13th century, a Benedictine monk known as Jilliam of Auxerre made significant contributions to the field of theology. His treatise, "Summa Aurea," was widely studied and regarded as an influential work on moral philosophy and ethics.
In the 15th century, a Scottish nobleman named Jilliam Douglas played a pivotal role in the Wars of the Roses. He was a staunch supporter of the House of Lancaster and fought alongside King Henry VI at the Battle of Towton in 1461, where he ultimately lost his life.
Another notable figure bearing the name Jilliam was an English explorer and navigator from the 16th century. Jilliam Baffin was renowned for his expeditions to the Arctic regions, where he discovered and mapped the body of water now known as Baffin Bay, located between Greenland and the Canadian Arctic Archipelago.
People
Jilliam + last name combinations
How many people share a full name with Jilliam 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
Jilliam: questions and answers
How many people in the U.S. are named Jilliam?
Name Census puts the figure at roughly 97 living Americans. We arrive at this by taking every SSA birth registration for Jilliam 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 3,533,550 US residents.
Is Jilliam a common name?
We classify Jilliam as "Very Rare". It ranks above 64.1% of all first names in the SSA dataset by living bearers. Across the full history of the data, 102 babies have been registered with this name.
When was Jilliam most popular?
The single biggest year for Jilliam was 1987, when 15 babies received the name. The fact that the average living Jilliam is about 39 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
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 Jilliam in that year. That makes it useful for spotting when the name rose, peaked, or faded.
Is Jilliam a female name?
Yes, 100.0% of people registered as Jilliam 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 Jilliam still being used today?
Yes. The SSA still recorded Jilliam 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 Jilliam 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.
Does every first name have Census demographic data?
No. The public Census first-name release only covers names that met the Bureau's publication rules, so many rarer names in the SSA files do not have a published Census demographic snapshot. In those cases, the page still shows the SSA trend, gender history, and state data.
How common is the name Jilliam?
For a quick modern estimate, our sister site HowManyOfMe.org answers that in one glance, with the living-bearer count front and centre.