The Siloam inscription or Shiloah inscription, known as KAI 189, is a Hebrew inscription found in the Siloam tunnel which brings water from the Gihon Spring to the Pool of Siloam, located in the City of David in East Jerusalem neighborhood of Silwan. The inscription records the construction of the tunnel, which has been dated to the 8th century BC on the basis of the writing style. It is the only known ancient inscription from ancient Israel and Judah which commemorates a public construction work, despite such inscriptions being commonplace in Egyptian and Mesopotamian archaeology.

The newer Siloam Tunnel, also known as Hezekiah's Tunnel, is a water tunnel that was carved within the City of David in ancient times, now located in the Arab neighborhood of Silwan in eastern Jerusalem. Its popular name is due to the most common hypothesis that it dates from the reign of Hezekiah of Judah, late 8th and early 7th century BC, and corresponds to the "conduit" mentioned in 2 Kings 20 in the Hebrew Bible. According to the Bible, King Hezekiah prepared Jerusalem for an impending siege by the Assyrians, by "blocking the source of the waters of the upper Gihon, and leading them straight down on the west to the City of David". By diverting the waters of the Gihon, he prevented the enemy forces under Sennacherib from having access to water. An older water system, sometimes called the Siloam Channel, partly fulfilled a similar purpose and dates back to the Canaanites.