The Castelli surname
In the 2000 U.S. Census, 3,176 people carried this name — #9,401 among all U.S. surnames, about 1 in every 84,700 people counted.
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In France’s civil register
France’s register of deaths holds 1,415 people named Castelli.
280 of them were born outside France. Those born in France came from 68 départements, most often Corsica.
Where it concentrates, on the mapWhere they were born
Fichier des personnes décédées, INSEE — Licence Ouverte 2.0 · deaths recorded in France since 1970, by place of birth.
In Switzerland’s population statistics
607 people named Castelli live in Switzerland.
They live in 18 of Switzerland’s 26 cantons, most of all in Ticino.
Where it concentrates, on the mapWhere they live today
Swiss Federal Statistical Office (FSO), «Surnames of the permanent resident population by canton», 2025, opendata.swiss · names with fewer than 3 bearers in a canton are not published.
In Belgium’s population register
At least 86 people named Castelli live in Belgium.
Statbel only publishes a name in a municipality when five or more people there share it, so the real number is higher. Most of them live in Liège.
Too few records to say where it concentrates region by region — these are plain counts, not shares.
Where they live today
Statbel (Statistics Belgium), family names of the population by municipality, 1 January 2026 — CC BY 4.0.
Nearby in the index
Surnames next to Castelli.
- Castella 273 · U.S. census
- Castellan 264 · U.S. census
- Castellana 437 · U.S. census
- Castellani 751 · U.S. census
- Castellano 9,732 · U.S. census
- Castellanos 20,985 · U.S. census
- Castellini 351 · U.S. census
- Castellino 173 · U.S. census
- Castello 3,140 · U.S. census
- Castellon 5,557 · U.S. census
- Castells 161 · U.S. census
- Castellucci 687 · U.S. census
When the index is not enough
This page says where Castelli is.
A volume says what happened to it.
Every page in the index is free and stays free. The Heritage Volume is the long form: the full paper trail, the arms, the crossing — bound, and yours.