The mikveh was discovered in 2009, in the Western Tunnel, and it located some 65 feet away from the Western Wall it self. According to Josephus the Jewish administrative center was located in this area at the at the foot of the Temple on the west side. The Talmud says that the Sanhedrin would meet in this building.
Dubbed as "Sanhadrin Mikveh" due to its construct and proximity to the first century administrative center of the city, this was one of the largest mikvah ever discovered. It has 11 steps and was used by the multitude of Jews entering the Temple Mount near Wilson’s Arch or Warren’s Gate. Joesphus wrote that the Jewish government’s administrative center was located in this area at the foot of the Temple on the west side.
Looking down on the large mikvah from the modern tunnel gallery, as it is now below the ground level of the Western Wall Tunnel. This highly decorated mikvah has the architectural and artistic style of some of Herod’s most magnificent works with finely dressed ashlar stones and the highest quality craftsmanship in decorating. This could be part of the Sanhedrin’s governmental building as well as their ritual bath.