"Siddim, Vale of" Dictionary
Easton's Bible Dictionary (1897)
Valley of the broad plains, “which is the salt sea” (Gen. 14:3, 8, 10), between Engedi and the cities of the plain, at the south end of the Dead Sea. It was “full of slime-pits” (R.V., “bitumen pits”). Here Chedorlaomer and the confederate kings overthrew the kings of Sodom and the cities of the plain. God afterwards, on account of their wickedness, “overthrew those cities, and all the plain, and all the inhabitants of the cities;” and the smoke of their destruction “went up as the smoke of a furnace” (19:24-28), and was visible from Mamre, where Abraham dwelt.
Some, however, contend that the “cities of the plain” were somewhere at the north of the Dead Sea.