The newer Siloam Tunnel (Hebrew: נִקְבַּת הַשִּׁלֹחַ, romanized: Nikbat HaShiloaḥ), also known as Hezekiah's Tunnel (תעלת חזקיהו, Te'alát Ḥizkiyáhu), 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 (2 Kings 20:20) 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" (2 Chronicles 32:30). By diverting the waters of the Gihon, he prevented the enemy forces under Sennacherib from gaining access to water. An older water system, sometimes called the Siloam Channel, partly fulfilled a similar purpose and dates back to the Canaanites (Bronze Age).
The idea of dating the tunnel to Hezekiah's period was derived from the Biblical text that describes construction of a water tunnel in his time. Scientific support for this, however, came from radiocarbon dates of organic matter contained in the original plastering as well as radiometry (uranium-thorium dating of speleothems). The dates were challenged in 2011 by new excavations that suggested an earlier origin in the late 9th or early 8th century BC.