It depends on your level if it is say hmmm level 40 then train in kanto or say level 80 go to the elite four AFTER you get all 8 kanto badges
Mount Silver is the best place to train feraligatr Lv 42 and ampharos lv 37.
Train a totodile to level 18 then croconaw to level 36. You can get a croconaw from Pokemon colosseum.
You can't catch feraligatr in leafgreen you need to get a croconaw from Pokemon colosseum or get a totodile from emerald or Pokemon xd gale of darkness either way you must train both to get feraligatr.
Goldenrod City in between the trade center and the train station hope this helps and Feraligatr i choose you!
Feraligatr
Feraligatr is a Water type pokemon.
Feraligatr cannot learn Sheer Cold.
Feraligatr learns crunch at level 32
Level 58 will feraligatr learn it
feraligatr learns hydro cannon at level 74
Feraligatr is #160 in the national pokedex, and it is a Water type Pokemon.
Feraligatr doesn't evolve. If you mean Croconaw, it evolves into Feraligatr at level 30.