Of all of Herod's building enterprises, the Temple Mount was certainly the greatest. His plan was to erect a sacred enclosure with the temple in its center. This layout was similar to other such enclosures built throughout the Hellenistic world and the Roman Empire.

According to Jewish Law, the location of the temple (on Mount Moriah) and its measurements were predestined by God (see The Temple Mount in Traditional Thought; Mishna, Middoth). Hence, Herod could not relocate or expand the temple itself. The only improvements that could be introduced were the construction of a taller building and the use of richer materials. The major construction effort therefore focused on the erection of a vast platform to carry the temple. Enlarging the area of the Temple Mount to the north, the west and the south, Herod created a platform 144,000 sq m in area; the eastern wall of the Temple Mount remained as it was due to topographical constraints, i.e, the Kidron Valley. The immence platform (480 m long, 280 m wide) was suppported by four tremendous retaining walls. Varied cavities beneath the huge platform were roofed by arcades designated to relieve the pressure on the walls; some of these underground spaces were later used for various purposes, e.g., Solomom's Stables and the Cave Synagogue.