If you cant get to Blackthorn you must go through ice path which is east of mahogany town but if its blocked off you must go to goldenrod and go to the radio tower and take on team rocket. or if you've beaten Clair go to the back of the gym and take on the dragon path
Crystal version.
you can't.
I'm pretty sure it should be the last badge before you go off to the elite 4:)
GET THE LAST BADGE......
The last gym leader is the boss rocket to get him to the gym beat team rocket at: Mt moon, Game corner, Pokemon tower, Silph co. After you do this get the 7th badge if you haven't then you can get the last badge in viridian city.
viridian city
to buy a ultra ball in Pokemon crystal version , you must go to blackthorn pokemart and pay 1200 for each one. but its kinda far in the game . the last gym leader lives in that town.
The last gym badge is in viridian city for Kanto. For Johto it is in Blackthorn city.
AnswerThe last HM in Pokemon Crystal is HM07 - Waterfall. This HM is found in Ice Cave.
Pokemon league
You get in right before getting the last badge.
Sunyshore city, where the last gym badge will be.