It's nice that Living DNA has updated its Polish regions. I can only add that I tried to keep the number of regions rather small. I think that 15 regions is enough. But if we wanted, we could distinguish many small sub-regions within each of these 15 regions.
Many small ethnographic sub-groups can be distinguished. For example:
Powislans (Powiślanie) - Northern Poland
Krajniaks (Krajniacy) - Northern Poland
Kuyavians (Kujawiacy) - Northern Poland
Kociewiaks (Kociewiacy) - Northern Poland
Borowiaks (Borowiacy) - Northern Poland
Dobrzyniaks (Dobrzyniacy) - Northern Poland
Chelmniaks (Chełmniacy) - Northern Poland
Mennonites (Mennonici) - Northern Poland
Podlachians (Podlasianie) - Sudovia-Podlachia
Poleshuks (Poleszucy) - Sudovia-Podlachia
Lipka Tatars (Lipkowie) - Sudovia-Podlachia
Sudovians (Suwalszczanie) - Sudovia-Podlachia
Starovers (Starowiercy) - Sudovia-Podlachia
Lachs (Lachy) - Polish Mountains
Polish Gorals* (Górale Polscy) - Polish Mountains
Spisoks (Spiszacy) - Polish Mountains
Oraviaks (Orawiacy) - Polish Mountains
Dolinians (Dolinianie) - Polish Mountains
Lemkos (Łemkowie) - Polish Mountains
Boykos (Bojkowie) - Polish Mountains
Hutsuls (Huculi) - Polish Mountains
*Polish Gorals can be further divided into smaller subgroups.
Pogorzans (Pogórzanie) - PL Mountains / Lesser PL / Red Ruthenia borders
Deaf Germans (Głuchoniemcy) - PL Mountains / Lesser PL / Red Ruthenia
Krakowiaks (Krakowiacy) - Lesser Poland
Lasowiaks (Lasowiacy) - Lesser Poland
Zaglebiaks (Zagłębiacy) - Lesser Poland
Vilamovians (Wilamowianie) - Lesser Poland
Halcnovians (Hałcnowianie) - Lesser Poland
Lasowiaks (Lasowiacy) - Lesser Poland
Sandomirians (Sandomierzacy) - Lesser Poland
Posaniaks (Posaniacy) - Lesser Poland
Lubliniaks (Lubliniacy) - Red Ruthenia
Rusyns (Rusini) - Red Ruthenia
Galicians (Galicjanie) - Red Ruthenia
Zaborowiaks (Zaborowiacy) - Red Ruthenia
Rzeszowiaks (Rzeszowiacy) - Red Ruthenia
Paluczans (Pałuczanie) - Greater Poland
Hazaks (Hazacy) - Greater Poland
Chwalimiaks (Chwalimiacy) - Greater Poland
Wielen Mazurs (Mazurzy Wieleńscy) - Greater Poland
Biskupians (Biskupianie) - Greater Poland
Kaliszaks (Kaliszacy) - Greater Poland
Poznaniaks (Poznaniacy) - Greater Poland
Tastaks (Taśtacy) - Greater Poland
Porzeczans (Porzeczanie) - Greater Poland
Szamotulans (Szamotulanie) - Greater Poland
Gostynians (Gostynianie) - Greater Poland
Hanobers (Hanobrzy) - Greater Poland
Bambers (Bambrzy) - Greater Poland
Kurpies (Kurpie) - Masovia
Varsovians (Warszawiacy) - Mazovia
Poborzans (Poborzanie) - Mazovia
Lowiczans (Łowiczanie) - Mazovia
Karaims (Karaimi) - Masovia
Silesians** (Ślązacy) - Upper Silesia
Opolans (Opolanie) - Upper Silesia
Cieszyniaks (Cieszyniacy) - Upper Silesia
Silesian Gorals (Górale Śląscy) - Upper Silesia
Walachs (Wałasi Śląscy) - Upper Silesia
Kashubians** (Kaszubi) - Pomerelia
Slovincians (Słowińcy) - Pomerelia
**Both Silesians and Kashubians can be further divided into smaller sub-groups.
Leczycans (Łęczycanie) - Central Poland
Sieradzans (Sieradzanie) - Central Poland
Mazurians (Mazurzy) - Warmia-Masuria
Warmiaks (Warmiacy) - Warmia-Masuria
Sorbs (Łużyczanie) - Lower Silesia
Oder Wends (Wendowie) - Neumark
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In former eastern Polish lands, we can distinguish at least 2 major groups:
North Kresowiaks (Pn. Kresowiacy)
South Kresowiaks (Pd. Kresowiacy)
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In addition we can distinguish major ethnic-national minorities, such as:
Germans*** (Niemcy) - settled in most regions of Poland
Polish Jews (Żydzi) - once widespread throughout Poland
Dutch (Olędrzy) - mainly west and north of Poland
Armenians (Ormianie) - mainly south and east of Poland
Scots (Szkoci) - dispersed throughout Poland
Ukrainians (Ukraińcy) - south-eastern Poland
Belarusians (Białorusini) - north-eastern Poland
Lithuanians (Litwini) - north-eastern Poland
Russians (Rosjanie) - mainly Starovers but not only
Czechs (Czesi) - including Czech Brethren refugees
Slovaks (Słowacy) - in southern Polish borderland
Hungarians (Węgrzy) - some historical settlements
Roma (Romowie) - dispersed throughout Poland
***We can distinguish many ethnographic/regional groups among East Germans.