Albert Barnes Commentary 1 Samuel 25:20

"And it was so, as she rode on her ass, and came down by the covert of the mountain, that, behold, David and his men came down toward her; and she met them." — 1 Samuel 25:20 (ASV)

The covert of the hill - This was probably a defile or glen, literally a “secret place,” as in 1 Samuel 19:2. She was riding down into this glen from one side, while David and his men were descending the opposite hill. It is perhaps mentioned that she came by this “secret place” because she chose this path to escape the observation of her husband or anyone else.