In Pokémon Diamond the Great Marsh can be found at Pastoria City. Please look on the map.
The Great Marsh.
You can find Yanma in Pokémon Diamond in the Great Marsh.
Pastoria's great marsh.
Its a rare Pokemon in the Great Marsh.
You can find it at great marsh,pastoria does this help?
you cant ,for some reason or another, you have to get Pokemon platinum and find it in the great marsh
I found it in the great marsh by fishing area 3
You can find one in the Great Marsh after you complete the Sinnoh Pokedex.
To get Breloom in Pokemon Diamond you need to evolve a Shroomish. Shroomish can be found in the Great Marsh after you obtain the National Pokedex.
in the grate marsh
talk to the person in the entry of great marsh. she will give you hm05 defog
Barboach can be caught using the Good Rod in many bodies of water in Pokemon Diamond. One of the areas where it is easy to find with the Good Rod is the Great Marsh.