“Sea of Chinneroth.” The Old Testament name for the Sea of Galilee. The name is plural here in Joshua 12:3. For more on the name, see commentary on Deut. 3:17.
“sea of the Arabah, even the Salt Sea.” The Arabah is the rift valley through which the Jordan River runs. The Sea of the Arabah is the Salt Sea, the Dead Sea, but the “Dead Sea” is never called the Dead Sea in the Bible. Rather, it is referred to by a characteristic that was more identifiable at the time, and called the “Salt Sea” or the “Sea of the Arabah.” The surface of the Dead Sea is the lowest place on the face of the earth, about 1300 feet below sea level.
“Beth-jeshimoth.” Beth-jeshimoth is below and west of Mount Nebo close to the north part of the Dead Sea.
“on the south under the slopes of Pisgah.” Sihon did not rule as far south right at the Dead Sea as he rules further east, on the plateau, where he rules to the Arnon River valley.