'Lowlands' in the Bible

The king made silver as plentiful in Jerusalem as stones; cedar was as plentiful as sycamore fig trees are in the lowlands.

Then the king of Aram's servants said to him, Their god is a god of the hills; that is why they were stronger than we: but if we make an attack on them in the lowlands, we will certainly be stronger than they.

And get together another army like the one which came to destruction, horse for horse, and carriage for carriage; and let us make war on them in the lowlands, and certainly we will be stronger than they. And he gave ear to what they said, and did so.