The present Bundesstraße 185 links the most important Residenz towns of the former Principality of Anhalt. Only the section between Aschersleben and Ermsleben lay on Prussian territory. This section was known as Prussian State Road No. 90a (preußische Staatschaussee Nr. 90a) which was completed in 1842.
The 64.7 km long Reichsstraße 185 between Dessau and Aschersleben was built around 1937. In the 1960s the road was extended as far as Alexisbad in the Harz mountains.