Hastings' Dictionary of the Bible (1898)
HACH'ILAH, HILL OF (the darksome hill), a place in Judah near Ziph, and where David with his 600 followers hid. 1 Sam 23:19; comp. 1 Sam 23:14-15, 1 Sam 23:18; 1 Sam 26:3. Conder was inclined to locate it at the ruins now called Yekin: "The hill Yekin is a bold promontory standing just at the edge of the plateau. It looks over the whole desert; the cliffs of En-gedi, the Dead Sea, and the heights of Moab are in full view. Just beneath the crest
of the hill is a hollow, with another knoll beyond. It is the head of a great valley, which soon becomes precipitous, running down into the desert. In this hollow are a spring and a cave. This I imagine is what is meant by the 'trench.' 1 Sam 26:5. David is said to have crossed over to the other side, and we may imagine him standing on one or other of the hill-tops and looking down on the king and his sleeping party in the hollow."