I have compiled here a list of Celtic tribes and the Y-haplogroups to which I assume they belonged. I have based this on modern Y-Haplogroup maps and my own knowledge of European history. Know that this is not set in stone or a decisive statement on my part, and I am entirely willing to edit the list should new data, ideas, or overlooked tribes be presented to me. Note also that these tribes are not themselves set in stone, but rather a general reference from my own predictions.
Use it as you please, as it is here for those who might be curious of such matters, and I have done a decent bit of research before hand. Remember to take it all with a grain of salt, however, as this is mostly not based upon grave samples, which I'd be more than happy to look into soon should updating be necessary.
Keltoi
Aedui (Western Alpine Foothills) - R1b (S28, L21) / G2a / T
*E and J not accounted for because they are likely from the Roman conquest
Arverni (Central Gaul) - R1b (S28, DF27) / G2a
*E and J not accounted for just as with the Aedui
Belgae (Seine to Rhine) - R1b (S28, L21, S21)
*S21 is iffy because it is largely from Franks, but it was likely present
*I1 not accounted for because it likely comes from Franks
Boii (Bohemia) - R1b (S28, S21) / R1a-M458 / I2a / I1?
*Hard to classify because of Germanic and Slavic migrations
*I1 is only a plausibility, but the others are likely
Cisalpine Gauls (Po Valley) - R1b-S28
*Very little E or J in presumably less Romanized parts of the Po Valley (Western Romagna)
Helvetii (Western Alps) - R1b (S28, S21) / G2a / E-V13
*May well be located at the core of Celtic spread and have S28 almost as dense as Cisalpine Gauls
*S21 was likely weaker than now, but still present given its unusual strength far from the Rhine
Norici (Styria) - R1b (S21, S28) / I2a / R1a-M458 / I1 / G2a
*I1 is likely present because of its weaker presence south matches Celtic spread
*S21 is most often seen as Germanic, but likely present judging by its particular strength in Upper Austria
Transalpine Gauls (Southern Gallic Coast) - R1b-S28
*Other haplogroups are only as strong as they are in Italy, so they likely come from Roman conquest.
Brythons
Armoricans (Britanny) - R1b (L21, DF27, S28)
*Meeting point of Brythonic, Iberian, and Gallic migrations, not much changed save for Norse settlers
Caledonians (Northern Britannia) - R1b-L21 / I2b
*Strongest area of I2b beyond central Germany
Hibernians (Ireland) - R1b-L21 / I2a
*I2a weak but still present as Connacht shows
Iceni and Regnenses (Eastern and Southern Britannia) - R1b (L21, S28) / I2b
*S28 is likely as Caesar and others note that coastal tribes were of Belgic origins. It is also particularly strong in the east today.
Silures (Southwestern Britannia) - R1b-L21
*Likely the “purest” of the Brythons, with little I2 or S28
Others
Celtiberians (North and Central Iberia) - R1b-DF27 / E-V13
*Likely descendants of Iberians and not Gauls - very little R1b that is not DF2
Scordisci (Central Balkans) - R1b (S21, Z2103) / I1 / I2a
*Most likely a group of Celts ruling over Illyrian natives, so they are very difficult
Here is a detailed map for your reference: http://www.historyfiles.co.uk/FeaturesEurope/Barbarian_Map52BC_max.htm
Use it as you please, as it is here for those who might be curious of such matters, and I have done a decent bit of research before hand. Remember to take it all with a grain of salt, however, as this is mostly not based upon grave samples, which I'd be more than happy to look into soon should updating be necessary.
Keltoi
Aedui (Western Alpine Foothills) - R1b (S28, L21) / G2a / T
*E and J not accounted for because they are likely from the Roman conquest
Arverni (Central Gaul) - R1b (S28, DF27) / G2a
*E and J not accounted for just as with the Aedui
Belgae (Seine to Rhine) - R1b (S28, L21, S21)
*S21 is iffy because it is largely from Franks, but it was likely present
*I1 not accounted for because it likely comes from Franks
Boii (Bohemia) - R1b (S28, S21) / R1a-M458 / I2a / I1?
*Hard to classify because of Germanic and Slavic migrations
*I1 is only a plausibility, but the others are likely
Cisalpine Gauls (Po Valley) - R1b-S28
*Very little E or J in presumably less Romanized parts of the Po Valley (Western Romagna)
Helvetii (Western Alps) - R1b (S28, S21) / G2a / E-V13
*May well be located at the core of Celtic spread and have S28 almost as dense as Cisalpine Gauls
*S21 was likely weaker than now, but still present given its unusual strength far from the Rhine
Norici (Styria) - R1b (S21, S28) / I2a / R1a-M458 / I1 / G2a
*I1 is likely present because of its weaker presence south matches Celtic spread
*S21 is most often seen as Germanic, but likely present judging by its particular strength in Upper Austria
Transalpine Gauls (Southern Gallic Coast) - R1b-S28
*Other haplogroups are only as strong as they are in Italy, so they likely come from Roman conquest.
Brythons
Armoricans (Britanny) - R1b (L21, DF27, S28)
*Meeting point of Brythonic, Iberian, and Gallic migrations, not much changed save for Norse settlers
Caledonians (Northern Britannia) - R1b-L21 / I2b
*Strongest area of I2b beyond central Germany
Hibernians (Ireland) - R1b-L21 / I2a
*I2a weak but still present as Connacht shows
Iceni and Regnenses (Eastern and Southern Britannia) - R1b (L21, S28) / I2b
*S28 is likely as Caesar and others note that coastal tribes were of Belgic origins. It is also particularly strong in the east today.
Silures (Southwestern Britannia) - R1b-L21
*Likely the “purest” of the Brythons, with little I2 or S28
Others
Celtiberians (North and Central Iberia) - R1b-DF27 / E-V13
*Likely descendants of Iberians and not Gauls - very little R1b that is not DF2
Scordisci (Central Balkans) - R1b (S21, Z2103) / I1 / I2a
*Most likely a group of Celts ruling over Illyrian natives, so they are very difficult
Here is a detailed map for your reference: http://www.historyfiles.co.uk/FeaturesEurope/Barbarian_Map52BC_max.htm
Last edited: