Architecturally, it reflects a synthesis of Hellenistic, Roman, and local Judean influences, illustrating Herod’s intent to project both regal authority and military dominance. The site also includes hydraulic installations designed to secure a reliable water supply. Upper Herodium functioned as the focal point of the entire complex, both symbolically and strategically, overseeing the surrounding landscape and controlling access to the lower urban and agricultural areas. Archaeological investigations have further identified it as the probable location of King Herod’s tomb, discovered in 2007, underscoring its significance as a dynastic and funerary center within the broader Herodian architectural program.

Josephus writes, "he built a wall round that top of the hill, and erected towers at the corners, of a hundred and sixty cubits high; in the middle of which place he built a palace, after a magnificent manner, wherein were large and beautiful edifices".
---- Wars 7 Chapter 6 Par 1.

The combination of fortress and palace is a uniquely Herodian innovation, which he repeated on several other sites, including Masada. The upper Herodium is 758 meters (2,487 feet) above sea level, located atop the highest peak in the Judaean Desert.

circa 20 BCE

Herodium Synagogue
The synagogue at Herodium is of the Galilean-type, featuring stone benches built along the walls and aisles formed by columns that supported the roof. It is one of the oldest synagogues in the Levant. Unlike much of Herod’s Palace the synagogue can still be seen and identified today. Herodium Synagogue is the perfect example of a first century open air synagogue. Four freestanding columns were added according to the known "synagogue typology".

circa 20 BCE

Eastern Tower
The eastern tower - the largest - was a massive, round tower on a solid stone base and measured 18 meters in diameter. It had several upper stories with elaborate rooms, probably for the use of the royal entourage. This eastern tower rose above the entire fortress, its roof commanding a panoramic view; it also served as a hiding place in times of danger. This was the keep that guarded the fortress. It used to be 3 stories high. Under the tower and encircling the whole structure, runs a double wall.

circa 20 BCE

Peristyle Garden
West of the eastern tower, are the remains of the peristyle garden. Columns stood around the outside with a roof to the wall outside the garden. This left a large area in the center open to the sky for trees, vines, and bushes. On the far ends (north and south) of the peristyle were semicircular niches where statues were placed.

circa 20 BCE

Large Cistern
Herod built an underground access to large cisterns that were built on the north-eastern side. As Josephus wrote in Wars 7 Chapter 6 Par. 1): "He also made a great many reservoirs for the reception of water, that there might be plenty of it ready for all uses... ". It was a large reservoir, which was used to collected rainfall for use during the dry seasons. It is the larger one, reached by descending steps from the courtyard. It is most likely not Herodian, because in his time the cistern was only reached from outside.

circa 20 BCE

Roman Bathhouse
The Roman bathhouse was excavated on the southwest side, which probably served the royal entourage and the king's guests. It comprised a number of rooms and pools, a caldarium (hot room) heated by the hypocaust system (the floor was raised on supports, allowing hot air to circulate below the floor, thus heating the room). The bathhouse walls were decorated in painted square patterns and in imitation marble. The floors were paved with colored mosaics in geometric and floral patterns, as well as with pomegranates, grapevines and grape clusters.

circa 20 BCE

Eastern Mikvah
During the Great revolt, the Zealots captured the fortress in 66 CE. They converted a public structure to a synagogue and added two Mikveh (baptismals), one near the structure and the other near the eastern tower.

circa 20 BCE

Underground Passages
These underground passages were cut as hiding places by Jewish fighters of the Bar Kokhba Rebellion (132-135) when Herodium was once more besieged by the Roman army.