C. F. Keil and Franz Delitzsch on Joshua 16:3

Jos 16:3

From this point “it went down westward to the territory of the Japhletites to the territory of lower Beth-horon,” or, according to Jos 18:13, “to the mountain (or range) which is on the south by lower Beth-horon.” The Japhletite is altogether unknown as the Asherite of this name cannot possibly be thought of (1Ch 7:32-33). Lower Beth-horon is the present Beit-Ur Tachta, a village upon a low ridge. It is separated from Upper Beth-horon, which lies farther east, by a deep wady (see at Jos 10:10, and Rob. iii. p. 59). “And to Gezer,” which was probably situated near the village of el Kubab (see at Jos 10:33). “And the goings out thereof are at the sea” (the Mediterranean), probably running towards the north-west, and following the Wady Muzeireh to the north of Japho, which was assigned to the Danites, according to Jos 19:46.