Its exact location is unknown. Some believe this was identical with the site of Samaria, whose name was given by Omri after he bought the estate of Shemer and then named the site Samaria
after the name of Shemer (1 Kings 16:24). So, Shamir = Shemer = Samaria.
But there are difficulties with this view.
It is more likely, based on the noun pattern, that
Samaria
(šomron) is derived fromShemer
(šemer) than fromShamir
(šamir).Shamir in Judges 10:1 is identified as being in the hill country of Ephraim, but Samaria was located in Manasseh.1
1 After Abimelech there arose to save Israel Tola the son of Puah, son of Dodo, a man of Issachar, and he lived at Shamir in the hill country of Ephraim.