Lake Sidihoni sits on the highland plateau in the interior of Samosir, about 9 kilometres from Pangururan, at an elevation above the surrounding Lake Toba. It is a small, shallow lake surrounded by rice fields and forest, unremarkable in itself but remarkable for its geographical position — it is often described as a lake on an island in a lake on an island (the island in question being Sumatra). The recursive geography is genuinely unusual.
The lake is accessible by road from Pangururan, or by a longer route across the island from Tuk Tuk. The surrounding plateau is cooler than the lakeshore and has a gentler, more agricultural character — rice paddies, buffalo, Batak villages without the guesthouses. It is worth the excursion for the plateau scenery as much as the lake itself. A scooter makes the trip easy; the roads across the interior are in reasonable condition.