Herod the Great was the king of Judea from 37 to 4 BCE. As a client king of Rome, Herod's moniker as "Great" was due more to his grand building program throughout the eastern Mediterranean world. Herod's building program generally ran from 35 to 10 BCE, with major works at Caesarea Maritima, Jerusalem, Herodium, Samaria, Jericho, and the desert fortresses of Judea.

After becoming governor of Galilee in 47 BCE then ruler of Judea, with the all-important confirmation of Roman emperor Augustus in 31 BCE, Herod became the supreme ruler in Palestine. With little opposition and peace at the borders, he was able to turn his fullest attention to his building projects. Herod enjoyed "great riches and large revenues" (Josephus, Antiquities 15.387) from the bitumen trade at the Dead Sea and the Jericho plantations. Taxes were another significant source; he imposed a poll tax, alongside property taxes, sales taxes, and duties on customs. Additionally, perhaps his greatest income flow came from trade through the port city of Caesarea and its colossal harbor. Herod's harbor generated funds from docking fees and import and export tariffs.

Herod directed over 30 projects with remarkable distances between them. For instance, Caesarea is 120 km (75 mi) from Jerusalem. Then, further afield, 800 km (500 mi) across the Mediterranean, was his shipbuilding work at Rhodes, while his infrastructure work at Antioch was 500 km (300 mi) to the north.

One of Herod's largest undertakings was the raising of Caesarea Maritima on the eastern Mediterranean coast. Built to further Rome's military and commercial interests, this project was not a matter of improving or adding infrastructure. Herod built the city of Caesarea from the ground up, complete with a temple, palaces, amphitheater, theatre, paved streets, and waterworks. For waste management, there was a sewer system, and for freshwater, he built a 10.5-km (6.5 mi) aqueduct. Laid out on a grid, four wide streets ran north and south (cardines), and twelve narrower decumani ran east and west. 16.5 m (54 ft) wide and almost 1.6 km (1 mile) long, the main thoroughfare, the Cardo Maximus, was bordered with Roman mosaics and impressively lined with 700 columns, certainly of the ornate Corinthian type that also adorned the temple.

The city lay within a fortified wall enclosing 164 acres (66 ha), and one of its most imposing features would have been the temple. Set on a platform of 100 x 90 meters (328 x 295 ft), its own base was 29 x 46 meters (95 x 150 ft). With Corinthian columns, it rose nearly 30 meters (100 ft) into the air, and as Josephus says, for those out at sea, it could be seen from "a great way off" (Antiquities 5.415). Josephus also mentions a theatre and an amphitheater. The theatre, as it commands a view of the sea, is still used today and accommodates an audience of 4,000 people. The amphitheater, in the northeast section of the city, hosted regional games every five years, including wrestling, boxing matches, and gymnastic events.

Of the "splendid palaces" built throughout the city (Wars, 1.408), perhaps reflecting his own grandiosity, the largest and most splendid would have been Herod's. The Promontory Palace was constructed south of the temple, on a lone promontory on the sea, with two tiers, known as the upper and lower palaces; the lower 80 x 55 meter (260 x 180 ft) structure, closest to the sea, boasted a semicircular colonnaded porch that looked out onto the water. From there, walking back into the building, perimeter rooms would have accessed an inner colonnaded courtyard, the space which was largely filled with a 35 x 18 meter (115 x 60 ft) freshwater pool. In the middle of the pool stood a square pedestal for statuary. With a stairway leading up to it, the Upper Palace was dominated by a large 64 x 42 meter (210 x 138 foot) colonnaded courtyard.

Finally, at Caesarea, almost as a separate project, Herod built the city's harbor. Also built new, it too was remarkable, not only because of its size but because it was artificial with no natural bay or promontory to build on. Using a combination of hydraulic concrete and huge stone blocks, some weighing up to 50 tons, it was constructed like a fortress at sea. Supporting a superstructure of curtain walls reaching over 9 meters (30 ft) and towers over 18 meters (60 ft), its breakwaters, which were laid out on a circular course, enclosed 40 acres of water.

One of Herod's main works was expanding and reinforcing the Temple Mount, then adding the Second Temple and other structures on top. Standing 137 m (450 ft) above the Kidron Valley, the rectangular platform at the east end of the city extended 35 acres over valleys and scarps. After Herod enlarged and reinforced the Temple Mount, within the outer fortified enclosure, the north, east, and western perimeters of the mount were lined with double colonnades. Then, at the south wall perimeter, Herod erected the Royal Portico, which Josephus describes, "To such as had not seen it, was incredible, and to such as had seen it, was greatly amazing" (Antiquities, 15.416). Consisting of 162 Corinthian columns in four rows creating three aisles with flat roofs, the roof of the middle aisle was raised to a greater height. Each column was 14 m (47 ft) tall and 1.5 m (5 ft) thick (Netzer, 167).

Next, near the middle of the Temple Mount was the inner enclosure of the temple proper. On a platform, Josephus says the height of its walls measured 25 cubits from inside the enclosure and 40 cubits from the outside (Wars, 5.196). Then, with the attached Women's Court facing east, the temple itself, containing the vestibule, altar, and sanctuary, was 100 cubits in length, 100 cubits in width, with its highest aspect, the sanctuary, being 100 cubits tall.

In Jerusalem, Herod's first project may have been the fortress he built at the northwest corner of the Temple Mount. Named Antonia, after Mark Antony, Josephus describes its magnificence as like a palace, and because of its "conveniences," it was like a city (Wars, 5.221). With four corner towers, the tallest tower rose to almost 30 m (100 ft), while the other three were 23 m (75 ft) tall.

To the west, in the upper city area, integrated into the west wall's fortification, Herod also built his palace. Perhaps his largest abode, some estimate its size to have been 300 x 100 m (984 x 328 ft). Josephus describes two vast banqueting and reception rooms that he "raised to a very great height and adorned them with the most costly furniture of gold and marble" (Antiquities, 15.318). Additionally, just north and adjacent to the palace, Herod also built three exaggeratively large towers, naming them Hippicus, Phasaelus, and Mariamne after a friend, his brother, and his wife – Phasaelus, the largest, was 18 m (60 ft) square and 18 meters tall.

12 km (7.5 mi) from Jerusalem, at Herodium, there were two main areas of construction: the mountain palace/fortress and Lower Herodium. The fortress, built to be seen from afar, was enigmatic in design and purpose. Unusually round in structure with little military value because it oversaw no important military or commercial routes, its function was as much a monument to Herod himself. The enclosure's walls were 30 m (98 ft) high, and as a palace lay within, the diameter of its structure was 64 m (210 ft). At cardinal points, with three half-circle towers protruding from the enclosure's outer contour, the whole wall system appears to have been flat at the top except for the one gargantuan round tower that faced east.

Then, downhill from the fortress, covering an area of 15 hectares, the Lower Herodium complex consisted of a 130 x 55 m (426 x 180 ft) palace with bathhouses, adjacent to a 130 x 110 m (426 x 360 ft) garden area, which surrounded a 69 x 45 m (226 x 148 ft) pool that, when filled, was 3 meters deep.

As the Romans defeated the Hasmoneans and destroyed their desert fortresses, and allowed Herod to rule in their place, Herod returned to rebuild them. While Herodian architecture at Alexandrium and Hyrcania is not yet identified, Herod lavishly hosted Marcus Agrippa at Hyrcania in 16 BCE and Alexandrium in 15 BCE, suggesting elaborate refurbishment, if not expansion. However, at Cypros, the namesake of his mother, material evidence of Herod's work abounds. While the desert fortresses were built on tall hills, protecting the vital north/south corridor leading to Jerusalem through the Jericho Plain and Judean Desert, this fortress was one of the loftiest.

Cypros rises 250 m (820 ft) above the Jericho Plain, and the summit presently occupies 1000 square meters (10,764 sq. ft). Herod built an elaborate fortress here with two Roman baths. Then, at Machaerus, 6.5 km (4 mi) east of the Dead Sea and 25 km (15 mi) south of the sea's northern end, Herod rebuilt the fortress and a palace that consisted of two wings surrounding two courtyards. As Herod also rebuilt the adjoining city, in both places, "no significant changes were introduced to the Hasmonean outlines." (Netzer, Architecture, 215)

Finally, at Masada, Herod accomplished several projects between 35 and 15 BCE. In the southern half, he built three mansions averaging around 18 x 16 m (59 x 52 ft) with plain interior courtyards open to the sky. In the central northern half, Herod built a 39 x 30 meter (128 x 98 ft) apartment building with suites surrounding a courtyard. To the north, he built what is believed to have been an administrative and storage center. In this same period, he began what is known as the Western Palace, with several additions that would come later. The two-story palatial structure included a courtyard and among other rooms: a reception room, the "mosaic room" (so called because of its elaborate geometric and floral designed floor), the king's suite, a bathhouse, and a stepped pool that served as a mikveh or ritual bath. Later additions to the Western Palace were six service and storage wings.

Additional improvements at Masada include a grand-scale water system at the northwestern slope and the erection of a fortified wall system with 27 towers that encircled almost all of the mount. Moreover, great emphasis was put on the northernmost area, with the installation of a huge complex of storage buildings. Then, at the northernmost tip, Herod built a three-tiered palace, each edifice uniquely designed. The upper edifice had – with a reception hall and two bedrooms – a semicircular colonnaded balcony that looked out over the landscape. The middle terrace held, as its main feature – presumably with a dome roof – a concentric reception hall with an outer colonnade, 16 m (52 ft) in diameter. Finally, the lower edifice consisted of a square central hall, 10 x 9 meters (33 x 29 feet), that was surrounded on all sides by colonnades.

Like at Machaerus, Herod's endeavor at the city of Samaria was primarily, at least for the acropolis, an as-was reconstruction. Successively occupied from the 4th century BCE by the Macedonians, the Ptolemaic dynasty, the Seleucid Empire, and the Hasmoneans, with Rome's takeover, it was rebuilt by Gabinius, the Roman governor of Syria in 55 BCE. Then, with Augustus' rise to power after the Battle of Actium in 30 BCE, Samaria was added to Herod's kingdom. In honor of Augustus, he named the city Sebaste, the Roman emperor's Greek title. Looking to gain the loyalty of the inhabitants, Herod rebuilt the city. Built on a significant rise, Josephus says the original fortified walls were 20 furlongs (4 km) in circumference. Within an expanse of 75 hectares was the temple complex. In front of the temple was a monumental ascent of stairs 24 m (79 ft) wide that led to a rectangular colonnaded forecourt. Mirroring the rectangular plan of the forecourt, the Temple of Augustus, towering above all other buildings, sat on a 4 to 5 m (13 to 16 ft) high platform. The perimeter base of the temple was 33 x 24 m (108 x 79 ft).

The other large building at Samaria, because of its elongated rectangular plan, is thought to have been a stadium. Because of its architectural ornamentation, mainly frescoes, this structure is believed to have been Herod's own contribution to Samaria. Proportionately enclosing a 193 x 55 m (633 x 180 ft) Doric-style colonnaded courtyard, the stadium was 205 x 67 m (672 x 220 ft).

At the garden city of Jericho, over an area of 1000 hectares, Herod's main contributions were his building of three palaces and a structure that uniquely integrated the features of an amphitheater and hippodrome. From south to north, the palaces were in close proximity. The earliest southernmost palace was Herod's first at Jericho. Built when his rank was subservient to Cleopatra, it sat lower than the Hasmonean palace. With two bathing areas and a colonnaded courtyard, it measured 87 x 46 m (285 x 151 ft).

After an earthquake damaged the Hasmonean palace and Herod regained control of Jericho from Cleopatra in 31 BCE, he built, in line and north of his first palace, his second structure, this time on higher ground with a better view of the landscape. This complex was essentially divided into two areas. In the upper level sat the 58 x 33 m (190 x 108 ft) palace built with standard rooms and hallways around a peristyle courtyard. Next, down steps to a lower level was a 60 x 35 m (197 x 115 ft) recreational space of a colonnaded outdoor pool and a bathhouse with the usual Roman-type frigidarium, tepidarium, and caldarium bathing areas.

Then, around 15 BCE, Herod built his third palace. Like his second concept, this complex was divided into a palace with a recreational area. Lying between the first and second palaces, Herod positioned this complex so that a wet weather stream (the Wadi Qelt) ran between the palace and its recreational space. The palace, 84 x 37 m (275 x 121 ft), housed two peristyle courtyards, a bathhouse, and a giant reception/dining hall. Then crossing south, on a bridge over the stream, was a colonnaded sunken garden 112 meters (367 ft) in length and 37 meters (121 ft) in width with features midway and across from each other of two caveas or semicircular terraced-like structures. East of the garden was a 90 x 40 m (295 x 131 foot) pool, then south of the pool and garden, directly in line with the palace's bridge, on an artificial hill sat another building of unique design. 16 meters (52 ft) in diameter, this square building housed a round room, lending itself to the idea of interior niches with statues. Continuing with his innovative genius, Herod's other large edifice at Jericho was a multipurpose building of a colonnaded hippodrome with an amphitheater at one end able to seat 3000 attendees. The race track has been estimated to have been in excess of 300 m (984 ft) in length and 80 m (262 ft) in width.

As to other projects within Herod's kingdom, some excavated, some mentioned by Josephus, Herod built and dedicated a small temple to Augustus at Panias, where the headwaters of the Jordan River flow. 50 km (31 mi) southeast of Panias, he built the village of Bathrya as a frontline defense against invasion from the Trachonites. Between Jerusalem and Caesarea, seeing the area's agricultural potential, naming it after his father, he founded the settlement of Antipatris. Another place with agricultural potential, 20 km (12 mi) north of Jericho and 50 km (31 mi) east of Antipatris, Herod built and named the town of Phasael after his brother. 20 km (12 mi) east of Jericho, at Betharamptha, he built a palace with a farm. Some 15 km (9 mi) east of Betharamptha, as a bulwark against the Nabateans, Herod fortified the city of Heshbon.

Near Gaza, as he restored the city of Anthedon, he renamed it Agrippeion after the Roman general Marcus Agrippa (63 to 12 BCE). 3 km (2 mi) north of Hebron at Mamre, he built, with large ashlar blocks, a 65 x 49 m (213 x 161 ft) enclosure. West of the Hebron Hills, at Khirbet al-Murak, he built a fortified villa. Outside his kingdom, but still in the land of Israel, at Ascalon, he erected sumptuous fountains, colonnaded halls, and a palace. At Ptolemais, he built a gymnasium. In Syria, in Tyre and Berytus, he constructed halls, porticoes, temples, and marketplaces. In both Sidon and Damascus, he built theatres. In Damascus and Tripolis, gymnasia. In Byblos, he repaired the city walls. In Lattakia, he built an aqueduct. Then, in Antioch, Herod built a colonnaded street with polished stone that was 4 km (2.5 mi) long.

The aesthetics of pools, gardens, running water, fountains, frescoes, niches, mosaic floors, and the creation of wide spaces with courtyards and colonnaded walkways all equal the scope and monumentality of the buildings themselves. Accordingly, when considering the size, complexity, architectural creativity, and adornment that went into his building program, along with the financial and organizational ability to pull it off, it is no wonder Herod is called "the Great".