An old Canaanite city between Lachish and Hebron. It also is the name of a cave region nearby.
The first reference to the city in the Bible is in the word "Adullamite" (someone from Adullam). It is used to describe Hirah, a friend of Judah. After Judah helped sell his brother Joseph into slavery, Judah left home and lived in Adullam with Hirah (Genesis 38:1, 12, 20).
Adullam was in the lowlands of Judah's tribal area (Joshua 15:35). Joshua conquered it, along with 31 other Canaanite royal cities (Joshua 12:15). King Rehoboam strengthened it along with 15 other cities (2 Chronicles 11:7). After the exiles' return from captivity in Babylon, people from Judah lived in Adullam again (Nehemiah 11:30).
A cave near Adullam was important several times in David's life. He hid in it when he fled from King Saul (1 Samuel 22:1). He also used it as a base in his war against the Philistines (2 Samuel 23:13–17; 1 Chronicles 11:15–19). David wrote Psalms 57 and 142 when he was in the cave of Adullam. Adullam is the modern-day Tell esh-Sheikh Madhkur.