They overlap completely.question for the Irish residents/experts
in terms of support do Hurling and Gaelic Football overlap much? Is it mostly down to personal choice or are there parts of the country where one is much bigger than the other?
There are no (I think none, but stand to be corrected) Hurling clubs, or Football clubs - there are just local GAA clubs. The club plays both sports - on the very same pitch, and most of the players play both, to some extent.
In terms of geographical strength - yes, some counties are big hurling counties, and others are stronger in football.
My relatives are all in Kilkenny, where hurling is KING, and who until fairly recently enjoyed a Fergie/Man Utd type grip on the championship (11 of 15 titles from 2000 onwards - but none since 2016 - they keep losing to Limerick in the semi or final).