Ashan was a town in the southwestern Judean foothills slightly northwest of Beersheba.
Ashan was originally in the tribe of Judah (Joshua 15:42). Then it became Simeon’s (Joshua 19:7). Finally, it was given to the Levites as a city of refuge (1 Chronicles 6:59).
David traveled in that area with his group of men who were not following the law (1 Samuel 30:30). The city of Ain mentioned in Joshua 21:16 probably refers to Ashan (this is different than the Ain in the northeast of Canaan, Numbers 34:11).
See Cities of Refuge.