Hall of Hewn Stones

The Hall of Hewn Stones, also known as the Chamber of Hewn Stone, was the meeting place, or council-chamber, of the Sanhedrin during the Second Temple period. The Talmud deduces that it was built into the north wall of the Temple in Jerusalem, half inside the sanctuary and half outside, with doors providing access both to the temple and to the outside. The chamber is said to have resembled a basilica in appearance, having two entrances: one in the east and one in the west. Buildings in the temple complex used for ritual purposes had to be constructed of unhewn stones.
According to the Talmud, the Hall of Hewn Stones is the traditional meeting place of the Great Sanhedrin when it functioned as a court with full sovereign powers including the power to impose criminal penalties.
The Sanhedrin stopped meeting in the Hall of Hewn Stones when the Roman Empire restricted Judaea's autonomy and removed the Sanhedrin's power to impose criminal penalties.