In terms of having the "marrying cousins" stereotype.
I see sooooo many articles about women being raped and killed in Uttar Pradesh. What's up with that area specifically?
It used to be very common in Tamil Nadu for an uncle to marry his niece. So common that the word for uncle (mama) can be used interchangeably with groom
There’s a whole lotta cousins that I ain’t met yet So you can imagine the shock I get There’s one of them I think I mighta dated back in school But that’s alright, in Alberta that’s cool
Corb Lund - Family Reunion
It's either the Free State or Limpopo. Though if I had to pick one it would be Limpopo, it's the only province where the majority of white people voted to keep and continue apartheid during the referendum in 1992. While I've never been to the US, that sounds like it would fit the Alabama stereotype. Though jokes about dating cousins is usually aimed at people from Brakpan and Danville, but those are specific towns which have their own character.
The south. It's always the south.
The question is: does it flip after passing the equator or is the law universal for both halves of the globe?
Nah, in the UK it's the midlands. Coventry, Birmingham, Leicester, and Loughborough can all go in the bin.
Podlasie in Poland, definitely. My friend's parents have both the same maiden name despite not being closely related. Their whole village has basically the same surname.