1 Kings 7:46

Overview - 1 Kings 7
The building of Solomon's house.
Of the house of Lebanon.
Of the porch of pillars.
Of the porch of judgment.
Of the house for Pharaoh's daughter.
13 Hiram's work of the two pillars.
23 Of the molten sea.
27 Of the ten bases.
38 Of the ten lavers,
40 and all the vessels.
Treasury of Scripture Knowledge

1 Kings 7:46  (King James Version)
In the plain of Jordan did the king cast them, in the clay ground between Succoth and Zarthan.

the clay ground
Hebrew the thickness of the ground. Succoth.
Genesis 33:17

Zarthan is supposed to have been situated in the tribe of Manasseh, west of Jordan, near Jezreel and Bethshan or Scythopolis, and not far from the Jordan. Succoth we know was situated east of Jordan, in the tribe of Gad, and according to Jerome, in the district of Scythopolis: hence the "plain of Jordan," where Hiram cast the brazen vessels, must be the plain in which that river runs, Zarthan and Succoth being probably nearly opposite each other; but whether the precise spot of his operations was on this side or the other side, is uncertain. In this place he found that particular clay that was proper for his purpose; and it being a considerable distance from Jerusalem, that city would not be annoyed by the smoke and noxious vapours necessarily occasioned by the process.

Joshua 3:16

2 Chronicles 4:17