SUPH, SUPHAH (sūf, Heb. sûph). KJV has “the Red Sea” for both names. Suph (Deut.1.1, asv, rsv, niv) is the place in front of which Moses repeated the law to Israel. The sea (yam sûph) that the Israelites crossed in their flight from Egypt should be called the Reed Sea rather than the Red Sea. See Red Sea. Suphah (Num.21.14, asv, rsv, niv) is also east of Jordan. Neither place can be identified.

SUPH sōōf (ס֜וּף, reeds). According to the RSV, a place of indefinite location where Moses expounded the law to Israel (Deut 1:1). The KJV, following the LXX and Vul., understands it to refer to the Red Sea (yam sūph). Its association with Paran, Hazaroth, and the Arabah, the valley of the Jordan and the Dead Sea which extends southward to the Gulf of Aqabah, a northern arm of the Red Sea, suggests that the KJV tr. is quite probable.

SUPHAH sōō fə (סוּפָ֔ה). An area in Moab which is cited in the Book of the Wars of the Lord (Num 21:14). Its association with the Brooks of Arnon suggests that it was E of the Dead Sea in the area of the Arnon and its tributaries. The RSV reads “Waheb in Suphah.” while the KJV understands Suphah to refer to the Red Sea (yam Suph).

International Standard Bible Encyclopedia (1915)

(cuph; plesion tes eruthras (thalasses); the King James Version Red Sea): As the verse stands, the place where Moses addressed the children of Israel is indicated as "beyond the Jordan in the wilderness, in the Arabah over against Suph" (De 1:1). the King James Version, following Septuagint, takes the name as a contraction of yam cuph (see Red Sea). The abbreviation is not found elsewhere. The name of the sea was not derived from that of a city; so we need not look in that direction. Knobel suggested Naqb es-Safa, a pass about 25 miles West-Southwest of the Dead Sea. But it is "unsuitably situated; nor does the name agree phonetically (for @@ ... agrees with ..., not with ...)" (Driver, "Deuteronomy," ICC, 4). No identification is possible.

Suphah is the region in which Vaheb is situated (Nu 21:14). It is probably identical with Suph of De 1:1. Tristram (Land of Moab, 50 f) suggested identification with Ghor es-Safiyeh], a small oasis East of the mud fiats of Es-Sebkhah], South of the Dead Sea; but "the sibilants do not correspond, and Safiyeh is a specifically Arabic term (Wetzstein in Delitzsch, Gen4, 586, note 2) which does not seem to be a likely explanation of Suphah" (Gray, "Nu," ICC, 285 f). This, and other questions of identification, must wait for solution until a more thorough exploration of the whole district has been accomplished.