Well there are Biblical borders, and then there are the Talmudic bordersthere are Biblical borders, and then there are the Talmudic borders. (Much of your question is addressed there). The Talmudic northern border is Ako (as given in Mishna Gittin Ch. 1). The Biblical northern border is addressed by Numbers 34:7--9:
34:7 This shall be your northern boundary. From the Mediterranean Sea, draw a line to Hor Mountain.
34:8 From Hor Mountain draw a line along the Chamath Highway, so that the extreme edge of the boundary is toward Tzedad.
34:9 The border shall then extend through Zifron, with its extreme end at Chatzar Eynan. This shall be your northern border.
Rabbi Aryeh Kaplan identifies "Chamath Highway" as the modern-day Homa, Syria. See his commentary for more. Most of the other locations identified by Rabbi Kaplan's translation can be found on Wikipedia and/or Google Maps.