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Isak

Isak. Attested in United States of America, Spain, Slovenia, Belgium, Denmark, borne by about 362 people in the registers this map holds.

The same name, spelt two ways

One systematic substitution — s for z, w for v, ch for h — where BOTH spellings are independently attested surnames. Kosina and Kozina are one man in two clerks' handwriting. Stronger than sounding alike, weaker than somebody having checked.

IsacIżakIssakIsach

What Wikidata says this name is

Copied from Wikidata, not worked out here. It is crowd-sourced and wrong in places, which is why the item is linked below rather than the claim simply repeated.

Q37005524 on Wikidata ↗ — the item every line above came from.

Where it came from

No place of this name is in the gazetteer, so this map says nothing about where the name came from. Search a surname anywhere else and you will be told an origin — that it is Latin, or Italian, or means «joyful». That is etymology, it is usually unsourced, and it is a different question from the one answered here.

Where it is borne, and where a record names it

Attested in 5 countries: United States of America, Spain, Slovenia, Belgium, DenmarkDenmark — attested, not countedBelgium — 5 peopleSlovenia — 26 peopleSpain — 29 peopleUnited States of America — 302 people
A dot is a country, not a place. It sits at the country's centre because a national register counts a country; nothing here says where in it these people are. A hollow ring is attested but not counted — Denmark publishes which surnames exist and not how many carry each, and a family archive finds a name without counting heads. Sizing those by a number nobody published would invent it. Blank is not absence. This draws the 5 countries where the eleven registers and eight archives behind this atlas attest the name. Most of the world has no surname register this project can read, and the ones that do and will not are listed with the reason.
Belgium, by commune. 5 people in 1 of Belgium's 565 communes, counted by Statbel. The biggest is Brussel with 5. This is the only country here that can be drawn this way — every other register counts a country and stops, so a blank elsewhere is a gap in what states publish, not in the name.
1 place drawn, the largest being BrusselBrussel — 5

Country by country

Each country below can carry up to three different kinds of evidence, and none of them is the same claim. A register is a head-count — a state counted these people. A record is one document naming the surname on that ground, narrower evidence and often much older. And a volume overlapping these dates is a document from the right place and years — never a document known to name this surname. None of the three ever means the name exists in that country and nowhere else, or that it exists nowhere but here.

United States of America

302 Borne — a state counted them — Frequently Occurring Surnames from the 2010 Census; Frequently Occurring Surnames from the 2000 Census.

Whose archive to write to

This atlas has no birth-year evidence for Isak in United States of America, so it cannot narrow United States of America's 528,875 volumes by date — see United States of America's own page for all of it.

Spain

29 Borne — a state counted them — Frecuencia de apellidos, Censos de población (INE).

Whose archive to write to

395 of 35,936 volumes held for Spain overlap the 1950s — the decades Isak is attested here. Too many to list, and this atlas does not know whether any one of them names Isak. The commonest kinds: Church and parish registers, Probate, land and notarial, Civil registration and vital records. See everything this atlas holds for Spain →

Slovenia

26 Borne — a state counted them — Family names, Slovenia, 2026 (SURS tables 05X1015S–05X1018S).

Whose archive to write to

This atlas has no birth-year evidence for Isak in Slovenia, so it cannot narrow Slovenia's 1,585 volumes by date — see Slovenia's own page for all of it.

Belgium

5 Borne — a state counted them — Family names by municipality, 1 January 2026 (Statbel, TA_POP_LST_2026).

Whose archive to write to

This atlas has no birth-year evidence for Isak in Belgium, so it cannot narrow Belgium's 24,426 volumes by date — see Belgium's own page for all of it.

Denmark

Borne — a state counted them — Navne registreret i Danmark, January 2020 (Danmarks Statistik, republished by Digitaliseringsstyrelsen).

Whose archive to write to

This atlas has no birth-year evidence for Isak in Denmark, so it cannot narrow Denmark's 4,099 volumes by date — see Denmark's own page for all of it.

Whose archive held that ground, and when

Every surname site can tell you a name is common somewhere. This one also knows which filing system held that ground in which years — and those are the two halves of one question: my people were called this, they were there, so who has the paper, and for which century. A name in Croatia before 1881 may sit in a military series and not a county one; a name in the Netherlands before 1811 has no civil record at all, only a baptism.

This is about the ground, not about your family. A register counting a name in a country says nothing about which village. And these are the pieces of a country this atlas has drawn, which in a large one may be a corner of it — Acadia reaches into Maine and is not a statement about the United States, and Bohemia's ground crosses into Poland. Each region's own page says which ground it covers. Where a country is missing below, nothing covers it yet.

United States of America
Slovenia
  • Central Istria 8 eras Aquileia → Habsburg → Napoleonic → Austria–Hungary → …
  • Carniola and the Slovene lands 8 eras Inner Austria → Austria → The Illyrian Provinces → Kingdom of Serbs, Croats and Slovenes, then Yugoslavia → …
Belgium
Denmark
  • Denmark 4 eras Denmark–Norway → Denmark, after the loss of Norway → Prussia, then the German Empire → Denmark

No record region is drawn yet for Spain — which is a gap in this atlas and not a statement about that country.

Find Isak on the map →

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