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Castor

#4,733 in 2025Boys' name

Possibly to excel, to shine

Castor has been given to 390 babies in the U.S. since 1998. In 2025 it ranked #4,733 of 13,926 boys’ names in use. Its peak year was 2016, with 29 recorded.

Babies named Castor, 2025

1 in 158,000

Castor over time, 1880–2025

Boys
010203018801900192019401960198020002020

Based on births in the U.S. Babies given the name each year. Hover the chart — or focus it and use the arrow keys — for any year. Gaps mean the name was given fewer than 5 times that year; these counts are unpublished.

Castor: meaning, origin, and history

Possibly to excel, to shine

Deeper origin not confirmed in the cited records

What Castor means

Castor may mean “to excel, to shine”.

American usage and historical context

In the United States, 390 boys were recorded with the name Castor between 1998 and 2025. Its highest annual count was 29 in 2016; its best national rank was #3,701 in 2016.

Over 5 years its rank fell, from #3,938 in 2020 to #4,733 in 2025. Over 10 years its rank rose, from #5,332 in 2015 to #4,733 in 2025.

Sources & methodologyReferences, data & attribution

Meaning, origin, and language notes draw on the references below.

American popularity figures use published Social Security Administration records for this exact spelling. Counts below five for a name, sex, and year are omitted.

How common is Castor?

Everything below is computed from the 2025 data — the most recent year available.

Among all babies, 2025
1 in 158,000
21 of 3,315,165 births
Among boys only
1 in 81,300
<0.01% of boys
Rank, 2025
#4,733
of 13,926 boys’ names in use
Coin-flip room size
109,425 kids
Even odds of a second one

Where Castor sits on the popularity scale

Rarest published (5 a year)#1 — Liam (20,818)

Chance at least one other child shares the name

If the other children were drawn at random from the 2025 national name distribution. Real classrooms cluster by region and community, so treat these as a floor, not a ceiling.

Class of 20Under 1%
Class of 30Under 1%
Grade of 100Under 1%
School of 500Under 1%

Put another way: gather 109,425 children born in 2025 and it's an even bet that one of them is another Castor. In a class of 30 the chance is Under 1%.

When Castors were born

Half of everyone ever recorded as Castor was born before 2016 — so the typical Castor is around 9 today.

Median birth year
2016
About 9 years old
Biggest decade
2010s
45.1% of all use
Born in the last 25 years
92.6%
A modern name
Recorded since 1950
390
People you could plausibly meet
Choose a decade

2010s — 45.1% of all recorded uses (176).

Is Castor rising or falling?

Rank movement and count movement can disagree — the number of distinct names in use keeps growing, so a name holding a steady count still slides down the list. Both are shown.

Rank vs 1 year ago
+1,507
Places climbed
Rank vs 5 years ago
−795
Places dropped
Rank vs 10 years ago
+599
Places climbed
Births vs 10 years ago
1.24×
More babies than then
Share of its own peak
72.4%
Peak was 2016 (29)
Years since peak
9
Years
Year-to-year steadiness
Volatile
29.3% average annual change
Best rank ever
#3,701
2016

Spellings of Castor

Castor is not the most common spelling — Carter is, with 63.1% against Castor's 0.12%.

Grouped by closeness of spelling (up to two letter changes), same sex, with a floor on all-time use. It catches Sophia/Sofia and Aiden/Ayden, and misses spellings that sound alike but look different, like Sean and Shawn.

Where Castor is used

Across 1910–2025, Castor was most concentrated in California — about 1 in — boys, against 1 in 3,069,616 across all states with data. It was least common in Texas (1 in —).

00 per 100,000

Most concentrated

  1. 1California1 in —
  2. 2Texas1 in —

Shading is the share of that state's recorded boys given this name, not the raw count — otherwise the map would just show which states are biggest. Unshaded states have no published records for this period. U.S. birth records suppress state-year counts below 5; state counts therefore don't add up to the national total. Every state links to its full rankings. Castor has too little recent state data to map, so this covers all years from 1910.

Castor around the world

Where Castor ranks in official birth records elsewhere in the world. Rankings only — the number of births isn’t comparable between places, so it isn’t shown.

  • England & Wales
    2008–2022
    #3,450
    in 2022
  • Canada
    2016–2016
    #2,441
    in 2016

Popularity data from Office for National Statistics and Statistics Canada. ONS data under Open Government Licence v3.0. StatCan data under Statistics Canada Open Licence.

Castor by the numbers

The raw record for each sex the name is used for.

As a boy's name

Rank in 2025
#4,733
Trend vs 5 yrs ago
Down 795
Best rank ever
#3,701
2016
Peak year
2016
29 that year
First recorded
1998
Last recorded
2025
All-time count
390
Count in 2025
21

Names similar to Castor

Matched on shared beginnings and endings, similar length, and comparable popularity.

CastleCasparCasmirCashelCastonCashusCastenCastinCashiusCaswellCassielCashisCasynCaspenCassieHeitorCashtynCashmirCasmerAlastorCashmereCashtenAstorCaspin

Sibling names for Castor

Names from the same era and popularity tier — the two things that make a sibling set feel deliberate — skipping lookalike spellings and shared initials.

Explore around Castor

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