Johann Georg Rohlmann and his wife Anna Maria settled in the Volga German colony of Merkel on 28 August 1766. They are recorded there on the 1767 census in Household No. 43.
The 1767 census records that Johann Georg Rohlmann came from the German area of Alsace.
- Pleve, Igor. Einwanderung in das Wolgagebiet, 1764-1767 Band 3 (Göttingen: Göttinger Arbeitskreis, 2005): 128.