Answer 1

Here is all the Information you are asking for.

The Hidden Grottos are located in the following areas:
Route 2
Route 3
Route 5
Route 6
Route 7
Route 9
Route 13
Route 18
Route 22
Route 23
Floccesy Ranch
Pinwheel Forest
Lostlorn Forest
Giant Chasm
Abundant Shrine

A total of 16 Hidden Grottos

Comments

There are 2 on Route 13 though, so that should be 16 in total.

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Oh thanks

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This has been asked before -_- http://pokemondb.net/pokebase/97131/where-are-all-the-hidden-grottos-in-pokemon-white-2