John Gill Commentary Judges 15:9

"Then the Philistines went up, and encamped in Judah, and spread themselves in Lehi." — Judges 15:9 (ASV)

Then the Philistines went up From Palestine, which lay low on the shore of the Mediterranean sea:

and pitched in Judah ; in the laud of Judea, which lay higher, particularly in the tribe of Judah, where they came with an army, and encamped there:

and spread themselves in Lehi ; their forces were so many, that they extended a considerable way, and particularly reached to Lehi, that is, which was afterwards so called; for it has its name by anticipation from the jaw bone, which it signifies, with which Samson slew many in this place, as after related.