The Guillou surname
In the 2010 U.S. Census, 119 people carried this name — #140,157 among all U.S. surnames, about 1 in every 2,500,000 people counted. That is up 13% from 105 in 2000.
Where the name comes from
The origin of the Guillou surname
Borrowed from French Guillou, itself from Breton.
From Wiktionary, the free dictionary (en.wiktionary.org) — entry «Guillou» (English), by Wiktionary contributors · licensed CC BY-SA 4.0 (creativecommons.org/licenses/by-sa/4.0) · excerpt, lightly adapted.
In France’s civil register
France’s register of deaths holds 9,435 people named Guillou.
74 of them were born outside France. Those born in France came from 94 départements, most often Finistère.
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 Argentina’s national register
At least 39 people named Guillou live in Argentina.
RENAPER only publishes a name in a province when more than ten people there share it, so the real number is higher. Most of them live in Tucumán.
Too few records to say where it concentrates region by region — these are plain counts, not shares.
Where they live today
RENAPER (National Registry of Persons, Argentina), surnames of residents by province, December 2021 — CC BY 4.0.
In Switzerland’s population statistics
26 people named Guillou live in Switzerland.
They live in 4 of Switzerland’s 26 cantons, most of all in Valais.
Too few records to say where it concentrates region by region — these are plain counts, not shares.
Where they live today
Swiss Federal Statistical Office (FSO), «Surnames of the permanent resident population by canton», 2025, opendata.swiss/en/dataset/nachnamen-der-standigen-wohnbevolkerung-nach-kanton3 · names with fewer than 3 bearers in a canton are not published.
In the Nordic population registers
20 people named Guillou is counted in Finland.
Finland counts its citizens, at home or abroad.
Counted, by country
Digital and Population Data Services Agency (DVV), Finland, surname statistics, August 2026 — CC BY 4.0.
Who carried it
People named Guillou,
with a public archive behind them.
-
Joseph Guillou 1787–1853 · composer -
Alfred Guillou 1844–1926 · painter -
Eugénie Guillou 1861–1933 · nun -
René Marie Guillou 1747–1832 · politician
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Allain Jacques Guillou 1799–1876 · adventurer
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Constant Guilloû 1812–1872 · photographer
Wikidata and Wikimedia Commons (CC0) · 10 lives in all are documented under this name.
Nearby in the index
Surnames next to Guillou.
- Guillermo 3,393 · U.S. census
- Guillet 568 · U.S. census
- Guilliot 109 · U.S. census
- Guillory 15,161 · U.S. census
- Guillot 4,457 · U.S. census
- Guillotte 992 · U.S. census
- Guilmain 173 · U.S. census
- Guilmet 192 · U.S. census
- Guimaraes 1,242 · U.S. census
- Guimond 1,749 · U.S. census
- Guimont 442 · U.S. census
- Guin 2,685 · U.S. census
When the index is not enough
This page says where Guillou 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.