Recorded 1922–2025 · United States
Gillian was most popular in 1999, when 1,030 American babies were given the name — ranking #581 that year. In 2025 it ranked #5,826, with 47 births. Across 1880–2025 the Social Security Administration has recorded 16,127 people named Gillian.
Gillian first appears in Social Security Administration records in 1922, which makes it about 103 years old as a recorded American name. It has been recorded in 89 of the 104 years since.
The Social Security Administration has recorded 16,127 American births named Gillian between 1880 and 2025. That is recorded US births, not a world population — it counts people issued a Social Security number at birth in the United States. Of those, roughly 15,682 are estimated to be alive today.
47 American babies were named Gillian in 2025, ranking #5,826 that year.
Gillian is falling. Across 2021–2025 it averaged 51 births a year, against 144 a year across 2011–2015 — a change of -65% over the decade.
Measured on recorded births. American births overall have fallen since 2007, so most established names lose births over any recent decade — a name can shed births and still hold its rank. Compare the rank above, which is measured against the other names of the same year.
Across the whole record Gillian is a girl’s name — 99.6% of the 16,127 Americans given it were girls and 0.4% were boys. In births since 2016 it is 99% girls and 1% boys.
Counted from every US birth the Social Security Administration recorded under this name, so it reflects use rather than opinion. A name given to fewer than five babies of one sex in a year is withheld at source and is not counted.
Roughly 15,682 Americans named Gillian are alive today — 97% of everyone ever recorded with the name. The median is 27 years old, and half are between 23 and 39.
An estimate, not a count. Recorded births are carried forward through the Social Security Administration’s 2023 period life table, by age and sex. That table describes mortality in one recent year, so it credits the oldest cohorts with today’s survival rather than the harsher rates they actually lived through — the further back a name peaked, the more this will overstate how many remain. It counts people issued a Social Security number at birth, not immigrants who arrived later.
How much more common the name is in each state than across the country as a whole.
See Gillian on the interactive charts
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Source: U.S.A. Social Security Administration. Years 1880–2025. namelegacy.org