Read Thread: I know how to list found HH's...
The new location of a HH is not made public, so that it's a surprise for the next finder. I guess you could contact the owner though.
I usually message the owner where I left the HH. I recently found an HH that was launched in January 2001 and the owner hadn't heard about it in a long time and was surprised it was still out there. The book was almost full!