Rieneck is a town in the Main-Spessart district in the Regierungsbezirk of Lower Franconia in Bavaria, Germany. Rieneck lies in the Würzburg …Rieneck is a town in the Main-Spessart district in the Regierungsbezirk of Lower Franconia in Bavaria, Germany. Rieneck lies in the Würzburg region between the southern foothills of the Rhön and the east side of the Spessart on the lower reaches of the River Sinn, 12 km northeast of Lohr am Main, and 39 km northwest of Würzburg. Administratively, it belongs to the Main-Spessart district in the Regierungsbezirk of Lower Franconia.