Castor

surname · English · Latin script

Recorded for both men and women· direction only, no split published

Castor is a surname, with more bearers in Peru than in any other country. In Réunion it is the 4th most common surname. It appears chiefly in English and Spanish, written in the Latin script. Recorded meaning: from Caistor (Lincolnshire), Caister (Norfolk), or Castor (Northamptonshire); first attested Osgod on Castre 972 OEByn.

rarermore common
  • LALaos1 in 226◐
  • USUnited States1 in 1.8K
  • PHPhilippines1 in 8.9K

carrying the name, one hue, darker where it is more common. Hover a country for its figure.

≈918K ●

across 13 countries

2 ●

recorded for this name

Sources
284 ●

76K records

Official registry-verified

1 in 65 ◐

Costa Rica

Spellings & scripts●

CastorLatin · English●67K records
คาสโตรThai · Thai●16 records

One other spelling is counted as the same name:

Locally spelled Castro in PE Peru, EC Ecuador, ES Spain and 4 more.

Spellings marked ● are how people bearing the name write it in our records; ○ marks a model's transliteration. Click a spelling to open its page.

Meaning & origin●

from Caistor (Lincolnshire), Caister (Norfolk), or Castor (Northamptonshire); first attested Osgod on Castre 972 OEByn

Sources 1

  • A Dictionary of English Surnames

Attested in 1 language in the etymology graph.

Where in the world●

Sorted by bearers counted by national registers, records where none counts.

Where Castor is recorded, by country
CountryMost common spellingSources
PE Peru—255,639△139 rec.1 in 125357KCastro11
US United States—184,134△39K rec.1 in 1.8K188KCastor284
AR Argentina—148,2160 rec.1 in 307148K—1
EC Ecuador—123,885△39 rec.1 in 136124KCastro9
ES Spain—123,156△174 rec.1 in 406123KCastro29
CR Costa Rica—78,7550 rec.1 in 6579K—1
PH Philippines#48126,36725K rec.—listedCastor64
LA Laos#2521,87545 rec.——Castro10
CH Switzerland—1,967△32 rec.1 in 4.3K2KCastor6
TH Thailand—1,9181.1K rec.—#70,747Castro50
GB United Kingdom—1,7711.7K rec.—listedCastor41
AU Australia—891918 rec.——Castor47

Roughly 256K people in Peru bear this name (about 1 in 125). Estimates project the name's share of our records onto national population, so each is only as good as the record base beside it — the Basis column gives that base; rows marked △ rest on fewer records than the estimate itself and are order-of-magnitude at best.

Country figures for a list of names, at full precision, are available under licence rather than by scraping this table. How that works.

Languages●

  • English67K53%
  • Spanish28K22%
  • Portuguese12K10%
  • French7.6K6%
  • German1.8K1%
Show as table
Languages in which the name is recorded
NameRecordsNote
English66,67553%
Spanish28,19822%
Portuguese12,32310%
French7,6196%
German1,7841%

Language is read off each record's context, not declared by the bearer; a share is of all records for this spelling.

Other names spelled this way◐

Castor is also recorded as 7 other names, grouped separately because the records behind them do not connect to the one described above.

  • French surname9.2K records spelled Castor7 spellings in the group

    Most recorded in France, Philippines, United States, Spain

    Languages: French, Catalan

    Also written Cástor, Càstor, Câstôr

  • a separate surname1.8K records spelled Castor2 spellings in the group

    Most recorded in United States, United Kingdom, Canada, Spain

    Also written Cástor

  • Indonesian surname1.5K records spelled Castor2 spellings in the group

    Most recorded in Philippines, Indonesia, United States

    Also written Cástor

  • Italian surname885 records spelled Castor2 spellings in the group

    Most recorded in Philippines, United States, Italy

    Also written Castore

  • Arabic surname528 records spelled Castor3 spellings in the group

    Most recorded in United States, Philippines, Saudi Arabia, Egypt

    Also written Càstor

  • Hindi surname337 records spelled Castor4 spellings in the group

    Most recorded in United States, Philippines, Canada

    Languages: Hindi, Urdu

    Also written Cástor

  • Danish surname278 records spelled Castor4 spellings in the group

    Most recorded in Denmark, United States, Norway, Philippines

    Languages: Danish, Norwegian Bokmål

    Also written Çästör

56 further groups record this spelling and are not listed here.

Grouping is the name graph's, not a register's: two spellings join a group when the evidence links them, so a group is a claim about the records rather than about the people.

Other recorded senses●

Castor is also recorded in 5 other lexicons, as a different name or as an ordinary word. These are senses of the spelling, not of the name above.

  • In English, A hat made from the fur of the beaver.

    as a wordkaikki.org Wiktionary extract (IPA + transliterations)

  • In French, beaver (aquatic mammal)

    as a wordkaikki.org Wiktionary extract (IPA + transliterations)

  • In Portuguese, beaver

    as a wordkaikki.org Wiktionary extract (IPA + transliterations)

  • In English, twin of Pollux in Greek myth; star

    as a namePronouncing Dictionary of Proper Names

  • In Spanish, Del griego Kástōr, "castor".

    as a nameDiccionario etimológico de nombres propios

Ordered by how much of this spelling's record each language holds, so a sense from a language the name is barely used in sits last rather than first.

Over time●

010203020002010202029 · 2016

Show as table
Castor in SSA — National Baby Names (1880–present), United States, 1998–2025
Yearrecords
199811
19998
200010
20019
20028
20037
20046
20059
200611
20078
20088
200913
20109
201110
201215
201317
201418
201517
201629
201714
201824
201923
202026
202117
202217
202311
202414
202521

US SSA — National Baby Names (1880–present) — 28 years between 1998–2025. One register's own figures, never a sum across registers: two registers counting the same people would double them.

Notable people with this name●

1850190019502000George A. Castor, b. 1855Annie Glenn, b. 1920Suzy Castor, b. 1936Jimmy Castor, b. 1940Betty Castor, b. 1941Élie Castor, b. 1943Chris Castor, b. 1960Jane Castor, b. 1965Kathy Castor, b. 1966Helen Castor, b. 1968

The ten people covered by the most Wikipedia language editions — a proxy for cross-cultural notability, which favours historical and Western figures over equally prominent contemporary ones — shown by birth year. Source: Wikidata (CC0).

Evidence●

Attested in 54 sources across 29 countries.

Official registers attesting Castor
CountryRegisterYearCountRank
BR BrazilIBGE — Censo 2022 Nomes no Brasil per-token lookup (v3 API, given+surname)—7K#1,740
US United StatesCensus Bureau — Surname Frequency 201020106.1K#5,722
US United StatesCensus Bureau — Surname Frequency 202020205.8K#5,732
US United StatesCensus Bureau — Surname Frequency 200020005.3K#5,944
VE Venezuelaasosab — SAIME ID-card names (1896–1996)—2.4K#651
ES SpainINE — Nombres más frecuentes (Padrón Municipal)—976#1,286
ES SpainINE — Padrón per-token widgets (current living counts, given + apellidos)—861#3,149
US United StatesCensus Bureau — First Name Frequency 2020 by sex2020448#22,077
FR FranceINSEE — Fichier des noms de famille (1891–2000)1991177—
SE SwedenSkatteverket — Sök hur många som har ett visst namn (living population)—165#5,995
BR BrazilBrasil.IO genero-nomes (IBGE Censo 2010 mirror, CC-BY-SA)—157#13,800
BR BrazilIBGE — Nomes (census name API)—118#33,482

Reference works 6

  • The Oxford Dictionary of Family Names in Britain and Ireland
  • Nederlandse FamilienamenBank (Dutch surname bank; ex-Meertens Instituut, now CBG)2007
  • Wikipedia given-name tokens
  • Wikipedia surname tokens
  • Wikidata name items (native-script + romanized given/family names)
  • jeantosti.com — Dictionnaire des noms de famille de France et d'ailleurs (Jean Tosti)

These works list the name; their figures are licensed and are not reproduced here.

Register rows as of the 2026-09-12 data build · 234 rows in the corpus for this spelling.

Frequently asked questions

How common is the name Castor?
We estimate roughly 918 thousand people bear Castor (counting its spellings and scripts) across 13 countries in our records.
In which country does Castor have the most bearers?
We estimate about 256 thousand people bear Castor in Peru, more than in any other country in our records, where it is most often spelled castro.
Where is Castor most common?
Measured as a share of residents rather than as a count, Castor is densest in Costa Rica — about 1 in 65 people — even though Peru holds more of our records for it.
How common is Castor compared with other names?
In Réunion, Castor is the 4th most common surname of 2,369 surnames recorded there.
What does the name Castor mean?
Recorded meaning: from Caistor (Lincolnshire), Caister (Norfolk), or Castor (Northamptonshire); first attested Osgod on Castre 972 OEByn
Query this name via API
curl https://api.mondonomo.ai/api/v1/name-graph/castor

The same payload this page is built from: spellings and scripts, countries and languages, related names, and the registers that attest the form. Rate-limited for casual use. Bulk access and licensing.

About this data

● measured from records◐ inferred from the name graph○ machine-generated

Data snapshot . Figures are rebuilt periodically and will change.

Statistics are aggregated from the Mondonomo name corpus; related names and etymology are inferred from the name graph; pronunciation and any machine-marked transliterations are model-generated. Read how the numbers are made, including their known failure modes, and where the data comes from.

Reference works we consult — surname dictionaries, official name registers, Wikidata and Wiktionary — are named directly, beside the claims they support. The per-country source counts also include datasets of person records: we publish how many there are and their authority tier, but not their names.

Cite this page Mondonomo, “Castor” — the 4th most common surname in Réunion. Data snapshot 2026-09-12.

See how Castor parses inside a full name →