The 19th Ersatz Division was formed on mobilization from 11 brigade replacement battalions (Brigade-Ersatz-Bataillone).

Thus, collectively, the 11 brigade replacement battalions represented troop contributions from 23 different infantry regiments.

The units of the 21st Mixed Ersatz Brigade were raised from the VI Army Corps area, which covered most of the Prussian Province of Silesia.

The units of the 45th Mixed Ersatz Brigade were raised from the XII (1st Royal Saxon) Corps area, which covered eastern Saxony.

The units of the 47th Mixed Ersatz Brigade were raised from the XIX (2nd Royal Saxon) Corps area, which covered western and southern Saxony.

Thus, after the dissolution of the 21st Mixed Ersatz Brigade, the division became a fully Saxon unit.