Dan was important northern city in Israel. The expression “from Dan to Beersheba” is the merism used to describe the entire land of Israel from the north (Dan) to the south (Beersheba).
1 Kings 4:25 And Judah and Israel lived in safety, from Dan even to Beersheba, every man under his vine and under his fig tree, all the days of Solomon.
Jeroboam built an altar at Dan, which became a center of idolatry. “But Jehu did not turn aside from the sins of Jeroboam the son of Nebat, which he made Israel to sin–that is, the golden calves that were in Bethel and in Dan” (2 Kings 10:29).
Dan is mentioned for the first time in Genesis 14 when Abraham rescued Lot from a coalition of kings. This is “The Gate of Three Arches” from the Canaanite period.
Genesis 14:14 When Abram heard that his kinsman had been taken captive, he led forth his trained men, born in his house, 318 of them, and went in pursuit as far as Dan.
The gate at Tel-Dan. The gate was more than an entry point, it was a place that had rooms for conducting business, storing merchandise, and sheltering people and animals.
The most important archaeological discovery is the inscription which mentions “The House of David.” It was discovered in 1994 and it dates back to the 8-9th century B.C.