You get it in the great marsh area.
Actually the area where you can find Pokemon in the Great Marsh changes each day. Try looking in the telescope on the second floor, if you can't find one after a couple tries, wait until the next day and try again.
It evolves at level 37.
First, you can get a croagunk in the Pastoria Great Marsh. In order for your croagunk to evolve, you must be good friends with it until it's happiness reaches at it's maximum. You can make him happy by obtaining the Soothe Bell, where you can get it from a maid in the second room to your left in a Pokemon Mansion between Pastoria City and Hearthome City. Use the Soothe Bell for croagunk to hold it. Hope it helped!
Safari Zone
Croagunk is #453 in the national pokedex, and it is a Poison-Fighting type Pokemon.
you see i havent got heart gold but i have got dimand and pearl and ive got a crogunk if there is a Pokemon marsh go there and you will find one .
That's easy, croagunk evolves at level 37-38.
im not sure...
POISEN & FIGHT
It evolves at level 37.
Level 37
He's in the Great Marsh
sudowoodo, croagunk, and happiny.
croagunk evolves at level 37
the symbol Pokemon of pastoria is croagunk as shown in the Pokemon episode diamond and pearl #082 cream of the craogunk crop. since croagunk is its symbol they have a sign in pastoria to help you feel as awesome as croagunk by looking like it through the sign in platinum.
Toxicroak is #454. You can get them at the Pastoria Great Marsh. It evolves from Croagunk at level 37, and you can also get Croagunk in the Pastoria Great Marsh.
I'm asuming that you mean croagunk which can be found in the safari zone.
Plain easy, get a Croagunk from the Great Marsh in Pastoria City and evolve it.