Into the wide open?

Located in the northwestern tip of India, the state of Arunachal Pradesh, covers a tremendous amount of terrain, not much smaller than the whole of Nepal. The former contained more than 40 hot springs so it's not surprising to see that Arunachal Pradesh has quite some thermal activity, though possibly less developed and / or visited. It's therefore understandable that there's less info on the internet available.

Reknown for the many different ethnicities, Arunachal Pradesh is distinctly remote, little roads offer any kind of access. Tawang district bordering both Tibet and Bhutan is accessible and contains largely Tibetean Bhudist ethnicities. As one of the most accessible mountain areas it's not surprising to find that (as is the case with Bhutan to it's east) there are a number of hot springs not far away from Tawang itself.

Tsachu Hot Spring is a bit of a language anomaly; Tsachu already being the Bhutanese name for a hot spring. It seems to be the most well-known, though not so easy to visit:

'Tsachu hot spring which can be reached by traveling by a light motor vehicle for two hours from Tawang up to Sarong Gonpa and trekking from there for another three hours'.

Do note that Tawang is 10 hours drive from the nearest airport ....

The hot spring of Thingbu is located 68 km away from Tawang town. Apparently a pony is the most used form of transport for the final stretch from the roadhead.

Other hot springs located in Tawang district are Kitpi (source) or Greng-khar (source), the former being the name of the village rather than the name of the hot spring (source PDF).

Mago hot spring is located nearer Jang:

'where the water is so hot that “yak meat is cooked in 20 minutes”'.

Despite the above being the most well-known(?) in Arunachal Pradesh, there are no first hand experiences shared. This contrasts with Dirang (West Kameng district, south of Tawang), famous for it's apples, kiwi's and yaks to which Roy Biswas has paid a visit:

'The other famed tourist spot is the Hot Water Spring, which is also the main attraction for locals, who supposedly take bath in the Hot Springs as its water is said to possess curative properties. However, I was most dejected after having undertaken a long trek down from the main road, as an Ecological Camp has come up at the site, with a Cafeteria right in front of the Hot Spring, which is not only blocks the view of the Hot Spring, but also creates more ecological hazards, rather than preserving the ecology there for which it is meant & sounds. The local environment department needs to take a look at this, before it gets too late to redeem the hot spring'.

Lower Dirang valley contains a hot spring near the village of Jia.

Located just inside of the Arunachal Pradesh - Assam border, the western town of Bhalukpong has it's own hot spring:

'Bhalukpong, which lies about 85 kilometers away from Bomdila on the foothills of Aka ranges, is an ideal picnic spot. The picturesque site is also a home to the Jia-Bharali river and a hot spring, which is believed to have a medicinal value (source)'.

More to the east, Anjaw district contains two hot springs, one named Walong circle the other Kibithoo circle.

As always when there is little reference material, some caution is required as often different names as used for the soak!