Adullam in Smiths Bible Dictionary

(justice of the people), Apocr. ODOLLAM, a city of Judah int he lowland of the Shefelah, Jos 15:35 the seat of a Canaanite king, Jos 12:15 and evidently a place of great antiquity. Ge 38:1,12,20 Fortified by Rehoboam, 2Ch 11:7 it was one of the towns reoccupied by the Jews after their return from Babylon, Ne 11:30 and still a city in the time of the Macabees. 2Ma 12:38 Adullam was probably near Deir Dubban, five or six miles north of Eleutheropolis. The limestone cliffs of the whole of that locality are pierced with extensive excavations, some one of which is doubtless the "cave of Adullam," the refuge of David. 1Sa 22:1; 2Sa 23:13; 1Ch 11:15

Link: https://bible-history.com/smiths/A/Adullam/