The Undercity

does exploring this area count for the overall % of the cantha exploration title?

The Undercity is underground and as such, needs to be remapped every time you go in there. It does not count towards the Canthan Exploration title.

thanks for info dude!

It used to - its southeast corner would let you uncover some fog over the river - but that changed when all "underground" locations got their own "mission maps." Now, you can no longer uncover anything from the Undercity.