Go through Mt. Moon.
i caught mine on the path from Cerulean city to Rock Tunnel
Cerulean cave located near cerulean city.
Vermilion city.
Go past mt moon go east and you will be in cerulean city.
inside cerulean cave near cerulean city.
I think you can only get it by using a thunderstone on an eevee. You get the eevee from Bill in Cerulean City.
cerulean city
north of cerulean city
by trading a poliwhirl for the jynx from the man in cerulean city
go south of cerulean city
You can find ditto in cerulean cave.
You can find Mewtwo in the Cerulean Cave.