John Gill Commentary Deuteronomy 3:17

"the Arabah also, and the Jordan and the border [thereof], from Chinnereth even unto the sea of the Arabah, the Salt Sea, under the slopes of Pisgah eastward." — Deuteronomy 3:17 (ASV)

The plain also, and Jordan
The plain by Jordan, the plains of Moab on the side of it, together with the river:

and the coast thereof ;
the country adjoining to it:

from Chinnereth even unto the sea of the plain, [even] the salt sea ;
that is, from Gennesaret, as the Targums of Onkelos and Jonathan, called the land of Gennesaret, (Matthew 14:34) , from thence to the sea of Sodom, the sea of the plain, where the cities of the plain stood, Sodom, Gomorrah, &c. and the salt sea, so called from the salt and nitrous waters of it, the lake Asphaltites:

under Ashdothpisgah eastward ;
mentioned among the cities given to the tribe of Reuben, (Joshua 13:20) rendered "the springs of Pisgah", (Deuteronomy 4:49) , the word having the signification of effusions, pourings out; so the Targums.