Recorded 1894–2025 · United States
Casimir was most popular in 1919, when 220 American babies were given the name — ranking #828 that year. In 2025 it ranked #4,351, with 73 births. Across 1880–2025 the Social Security Administration has recorded 5,248 people named Casimir.
Casimir first appears in Social Security Administration records in 1894, which makes it about 131 years old as a recorded American name. It has been recorded in 131 of the 132 years since.
The Social Security Administration has recorded 5,248 American births named Casimir 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 1,649 are estimated to be alive today.
73 American babies were named Casimir in 2025, ranking #4,351 that year.
Casimir is rising. Across 2021–2025 it averaged 58 births a year, against 29 a year across 2011–2015 — a change of +96% 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 Casimir is a boy’s name — 0.0% of the 5,248 Americans given it were girls and 100.0% were boys. In births since 2016 it is 0% girls and 100% 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 1,649 Americans named Casimir are alive today — 31% of everyone ever recorded with the name. The median is 29 years old, and half are between 10 and 65. That is a wide band, the mark of a name in steady use across generations rather than a passing fashion.
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 Casimir on the interactive charts
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Source: U.S.A. Social Security Administration. Years 1880–2025. namelegacy.org