The auxiliary missionary hospital at Ambarita was probably established about 1919. From that year onward  the hospital is mentioned in the Annexes of the Koloniaal Verslag, which mention the annual amounts of subsidy attributed to each hospital. E.g. Annex O of the Koloniaal Verslag 1930 mentions an amount of ƒ 480 for personnel and of ƒ 1206,25 for other expenses. The hospital was a category 1 hospital, a small hospital with a capacity of 10 to 25 beds.

Ambarita was situated on the island Samosir in the Lake Toba. It belonged to the Residency Tapanoeli on the Western Coast of Sumatra. The inhabitants belonged to the Batak people.