The B 23 starts at the B 472 (bypass Schongau - Peiting) exit Peiting-south in the Weilheim-Schongau district and initially leads to Rottenbuch.

A few years ago, this stretch was in a poor state of development, during which some more serious accidents have occurred.

After the road cross the village, it achieve the “Ettaler Sattel” (869 NHN) the highest point on the route.

After B 23 has crossed Griesen, the route ends at the border with Austria (Tyrol), where it merges into the Austrian B 187 (towards Lermoos, Fernpassstraße, Inn valley).

The most difficult part of this route led from Rottenbuch to Bad Bayersoien by Echelsbach gorge.

In 1991, following the release a segment of the bypass Schongau - Peiting the beginning of the B 23 changed to B 17 exit Peiting-West.

The relocation to the present location was made after completion of bypass Schongau - Peiting in 1997 In May 2000 the Farchanter Tunnel was opened.