Recorded 1953–2025 · United States
Reilly was most popular in 1997, when 543 American babies were given the name — ranking #870 that year. In 2025 it ranked #3,355, with 108 births. Across 1880–2025 the Social Security Administration has recorded 10,088 people named Reilly.
Reilly first appears in Social Security Administration records in 1953, which makes it about 72 years old as a recorded American name. It has been recorded in 52 of the 73 years since.
The Social Security Administration has recorded 10,088 American births named Reilly 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 9,941 are estimated to be alive today.
108 American babies were named Reilly in 2025, ranking #3,355 that year.
Reilly is falling. Across 2021–2025 it averaged 114 births a year, against 225 a year across 2011–2015 — a change of -49% 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 Reilly is a unisex name — 54.8% of the 10,088 Americans given it were girls and 45.2% were boys. It changed hands: since 2024 it has gone mainly to girls, having gone mainly to boys before that. In births since 2016 it is 54% girls and 46% 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 9,941 Americans named Reilly are alive today — 99% of everyone ever recorded with the name. The median is 22 years old, and half are between 16 and 27. That is a narrow band: Reilly arrived and faded within about a decade rather than staying in steady use.
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 Reilly on the interactive charts
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Source: U.S.A. Social Security Administration. Years 1880–2025. namelegacy.org