Which city is near to Takachiho Gorge?

I am planning to visit Yufuin, Beppu, Kumamoto , Kagoshima and Miyazaki. Was very enchanted by the rail road going through takaciho gorge and i am staying a night in Kirishima Iwasaki hotel. Can anyone advise me which town is nearer to reach takachiho?

There is no railroad going through Takachiho Gorge. There used to be a train connecting Nobeoka with Takachiho, but it was discontinued, although the upper most section is scheduled to re-open as a sightseeing train. But it does not run through Takachiho Gorge.

Can anyone advise me which town is nearer to reach takachiho?

Among the cities listed, Miyazaki is the city closest to Takachiho, about a 2.5 train and bus ride away. Kumamoto is about a 3 hour bus ride away.

Thanks Uji.
So how should I go from Kirishima Iwasaki hotel to the Takachiho ? By limited express then what bus ?
Is it a hiking or walking to the gorge ?

So how should I go from Kirishima Iwasaki hotel to the Takachiho ?

The fastest is probably to take the bus from the Iwasaki Hotel to Kirishima Onsen Station, then a limited express train to Miyazaki, another train to Nobeoka and then the bus to Takachiho.

Is it a hiking or walking to the gorge ?

There is a nice trail along the gorge, that is about 1 kilometer long (20-30 minutes at a slow pace). And it is possible to rent a rowing boat in the gorge.

Thanks again ! so is possible to do it as day trip ?
Please advise whether i should buy a 3 day bus pass and 5 days JR pass for 8 days in Kyushu or JR- 3 days northern kyushu pass and 5 days pass. The places I planned to visit Yufuin, Beppu, Kumamoto, Kagoshima, Miyazaki and back to Fukuoka.

so is possible to do it as day trip ?

Possible but not recommended! You would be spending most of your day on board of trains and buses.

The places I planned to visit Yufuin, Beppu, Kumamoto, Kagoshima, Miyazaki and back to Fukuoka.

Then, I recommend to circle the island: Fukuoka - Yufuin - Beppu - Miyazaki - Kagoshima - Kumamoto - Fukuoka

If you travel the entire route by express trains, regular tickets would probably cost you around 25,000 to 30,000 yen.

Thanks Uji, if not recommend as day trip, how would you recommend I do ? Is there any town nearby that I can stay overnight?

Why not stay in Takachiho? There are quite a few of hotels and ryokan available.

Good Idea ! so can I make use of the 3 days JR northern kyushu pass from Takachiho to Beppu ? Or is there a bus that I can take and how much will it cost ?

so can I make use of the 3 days JR northern kyushu pass from Takachiho to Beppu ?

No, the northern pass is not valid in Miyazaki Prefecture, where Takachiho is located. Furrthermore, Takachiho cannot be accessed by JR transportation.

Or is there a bus that I can take and how much will it cost ?

I don't think there is a direct bus. Instead, take a bus from Takachiho to Nobeoka Station (90 minutes, 1710 yen) and a train from there to Beppu (2 hours, around 4000 yen).