Caesarea (/ˌsɛzəˈriːə, ˌsɛs-, ˌsiːz-/), also Caesarea Maritima, Caesarea Palaestinae or Caesarea Stratonis, was an ancient and medieval port city on the coast of the eastern Mediterranean, and later a small fishing village. It was the capital of Roman Judaea, Syria Palaestina and Palaestina Prima, successively, for a period of c. 650 years and a major intellectual hub of the Mediterranean. Today, the site is part of the Caesarea National Park, on the western edge of the Sharon plain in Israel.

The site was first settled in the 4th century BCE as a Phoenician colony and trading village known as Straton's Tower after the ruler of Sidon. It was enlarged in the 1st century BCE under Hasmonean rule, becoming a Jewish village; and in 63 BCE, when the Roman Republic annexed the region, it was declared an autonomous city. It was then significantly enlarged in the Roman period by the Judaean client King Herod the Great, who established a harbour and dedicated the town and its port to Caesar Augustus as Caesarea.

During the early Roman period, Caesarea became the seat of the Roman procurators in the region. The city was populated throughout the 1st to 6th centuries CE and became an important early centre of Christianity during the Byzantine period. Its importance may have waned following the Muslim conquest of 640 when the city, then known in Arabic as Qisarya (قيسارية), lost its status as provincial capital. After being re-fortified by Muslim rulers in the 11th century, it was conquered by the Crusaders, who strengthened and made it into an important port, which was finally slighted by the Mamluks in 1265.

Qisarya was a small fishing village in the early modern period. In February 1948, during the 1948 Palestine war and Nakba, some of its population fled following an attack on a bus by the Zionist militant group Lehi, and the remainder were expelled by the Palmach, who subsequently demolished its houses. The ruins of the ancient city beneath the depopulated village were excavated in the 1950s and 1960s for archaeological purposes.

Whilst the name Caesarea was frequently used alone for the subject of this article, various markers were used to differentiate the location from these other locations; these include "Palaestina" ("of Palestine"), "Maritima" ("by the sea"; Greek: Παράλιος Parálios), "Sebaste" and "Stratonis". "Palaestina" is the most common term used in ancient sources, but, since the creation of Israel in 1948, historians in the West have tended to use the term less frequently.

The Latin name Caesarea also referred to several other cities in the region, notably Caesarea near Mount Hermon and Caesarea the capital of Cappadocia.

Stratonos pyrgos (Straton's Tower) was founded in the 4th century BCE by Abdashtart I, or Straton I king of Sidon. It was first established as a Phoenician colony and trading village. In 90 BCE, Jewish ruler Alexander Jannaeus captured Straton's Tower as part of his policy of developing the shipbuilding industry and enlarging the Hasmonean kingdom. Straton's Tower remained a Jewish settlement for two more generations, until the area became dominated by the Romans in 63 BCE, when they declared it an autonomous city.

Caesarea was built in Roman Judea under the Jewish client King Herod the Great during c. 22-10/9 BCE near the ruins of the small naval station of Straton's Tower. The site, along with all of Judea, was awarded by Rome to Herod in 30 BCE. The pagan city underwent vast changes under Herod, who renamed it Caesarea in honour of the Roman emperor, Caesar Augustus. Caesarea was known as the administrative, economic, and cultural capital of the Judean province from this time.