Gihon

a stream. (1.) One of the four rivers of Eden (Gen. 2:13). It
has been identified with the Nile. Others regard it as the Oxus,
or the Araxes, or the Ganges. But as, according to the sacred
narrative, all these rivers of Eden took their origin from the
head-waters of the Euphrates and the Trigris, it is probable
that the Gihon is the ancient Araxes, which, under the modern
name of the Arras, discharges itself into the Caspian Sea. It
was the Asiatic and not the African "Cush" which the Gihon
compassed (Gen. 10:7-10). (See EDEN T0001127.)

(2.) The only natural spring of water in or near Jerusalem is
the "Fountain of the Virgin" (q.v.), which rises outside the
city walls on the west bank of the Kidron valley. On the
occasion of the approach of the Assyrian army under Sennacherib,
Hezekiah, in order to prevent the besiegers from finding water,
"stopped the upper water course of Gihon, and brought it
straight down to the west side of the city of David" (2 Chr.
32:30; 33:14). This "fountain" or spring is therefore to be
regarded as the "upper water course of Gihon." From this
"fountain" a tunnel cut through the ridge which forms the south
part of the temple hill conveys the water to the Pool of Siloam,
which lies on the opposite side of this ridge at the head of the
Tyropoeon ("cheesemakers'") valley, or valley of the son of
Hinnom, now filled up by rubbish. The length of this tunnel is
about 1,750 feet. In 1880 an inscription was accidentally
discovered on the wall of the tunnel about nineteen feet from
where it opens into the Pool of Siloam. This inscription was
executed in all probability by Hezekiah's workmen. It briefly
narrates the history of the excavation. It may, however, be
possible that this tunnel was executed in the time of Solomon.
If the "waters of Shiloah that go softly" (Isa. 8:6) refers to
the gentle stream that still flows through the tunnel into the
Pool of Siloam, then this excavation must have existed before
the time of Hezekiah.

In the upper part of the Tyropoeoan valley there are two pools
still existing, the first, called Birket el-Mamilla, to the west
of the Jaffa gate; the second, to the south of the first, called
Birket es-Sultan. It is the opinion of some that the former was
the "upper" and the latter the "lower" Pool of Gihon (2 Kings
18:17; Isa. 7:3; 36:2; 22:9). (See CONDUIT T0000877; SILOAM
T0003433.)