Nephtoab is probably the modern “Ain Lifta”, two miles and a half northwestward of Jerusalem: and Mount Ephron is conjecturally connected with the city Ephrain 2 Chronicles 13:19 or Ophrah Joshua 18:23.
Related Commentaries of Joshua 15:9
Joshua 15:9
9 And the border was drawn from the top of the hill unto the fountain of the water of Nephtoah, and went out to the cities of mount Ephron; and the border was drawn to Baalah, which is Kirjathjearim: