Nowhere. It is a common misconception that the people of Yorkshire say "nay", but in reality, it isn't true. You might get the odd old geezer using it from time to time, but it has become all but extinct from common speech.

It is still used formally in Parliament, but that has more to do with tradition.

Yorkshire.

As in 'nay lad t'pubs shut early on Sundays'

Parliament

Horses say nay.

TROLL !! Go get a life !!