North Sumatra, Samosir Mountains

Written by on July 16, 2012 in Sumatra Mountains with 0 Comments

North Sumatra, Samosir  Mountains



This Ribu is the highest point on the volcanic island of Samosir, which lies within the vast Toba caldera complex – a landscape formed 74,000 years ago by the largest volcanic explosion in the history of the world. It was so enormous that it is thought that the eruptions nearly wiped out all human life on the planet. Lake Toba is Earth’s largest volcanic lake, measuring a staggering 100 kilometres by 30 kilometres. From Tuk Tuk, the flattish ridge of the island is clearly visible, and the highest point lies in forest just 4km (in a straight line) from Tuk Tuk.

Strangely, it is very uncommon for people to request a guide for a hike to the highest point of the island. There are several hikes from Ambarita and Tomok, but none of the usual routes actual goes close to the highest point of the island. Whereas much of Samosir island is deforested, a reasonable amount of forest remains on the flat summit ridge. This means that views are limited at the very top but there are some excellent views over the lake on the route up into the hills.

Farm tracks criss-cross the island but they are so bumpy that you would need either a farm vehicle or – better still – a brave ojek driver! You can reach the top of the island in about one and a half hours from Tuk Tuk by ojek – the route leads on good quality roads through the messy market area of Tomok and then up into the hills, past a lovely viewpoint over the lake, a waterfall before reaching close to the top of the ridge. At a signpost near a farm you need to take a right turn along the bumpy farm track for about 7km. Once in the forest there are only limited views but the forest is reasonably pleasant and there are one or two large ponds near the summit which are very attractive in the early morning light.

The farm tracks goes to within 100 metres of the true summit, which is in dense forest and would appear to be inaccessible (please contact us if you have found this not to be the case!). You can return the same way back to Tuk Tuk in about an hour.

Bagging information by Daniel Quinn


Getting there

The whole Toba area is one of Indonesia’s most visited places, so getting to/from Samosir from Sumatra’s capital, Medan, is straightforward. It is better to arrange transport in advance because the prices of taxis at Medan airport are ridiculous! It takes about 4 hours in a private car from Medan to Parapat (for the 30 minute ferry ride to Tuk Tuk). Shared taxisfrom Parapat to Medan cost just Rp75,000 per person and leave almost every hour during the day. It’s best to reserve in advance in either Parapat or Tuk Tuk.


Plenty of places to stay in Tuk Tuk and nearby. To suit all budgets and tastes.


None required.

Water sources

Not needed if you take an ojek all the way! Otherwise, take a couple of small bottles for the ridge walk

Country: Indonesia

Subregion Name: Sumatra (Indonesia)

Volcano Number: 0601-09=

Volcano Type: Caldera

Volcano Status: Holocene

Last Known Eruption: Unknown

Summit Elevation: 2157 m 7,077 feet

Latitude: 2.58°N 2°35’0″N

Longitude: 98.83°E 98°50’0″E

The 35 x 100 km Toba caldera, the Earth’s largest Quaternary caldera, was formed during four major Pleistocene ignimbrite-producing eruptions beginning at 1.2 million years ago. The latest of these produced the Young Toba Tuff (YTT) about 74,000 years ago. The YTT represents the world’s largest known Quaternary eruption, ejecting about 2500-3000 cu km (dense rock equivalent) of ignimbrite and airfall ash from vents at the NW and SE ends of present-day Lake Toba. Resurgent doming forming the massive Samosir Island and Uluan Peninsula structural blocks postdated eruption of the YTT. Additional post-YTT eruptions include emplacement of a series of lava domes, growth of the solfatarically active Pusukbukit volcano on the south margin of the caldera, and formation of Tandukbenua volcano at the NW-most rim of the caldera. Lack of vegetation suggests that this volcano may be only a few hundred years old (Chesner and Rose, 1991).

Tags: , , ,


If you enjoyed this article, subscribe now to receive more just like it.

Subscribe via RSS Feed

Leave a Reply