Treśka

The same name, inflected

A rule of the language rather than an opinion. Polish makes Kowalski and Kowalska of one surname.

TreskiTreśky

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.

Tresca

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

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.

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.