Deuteronomy 4:42-46

That the slayer might flee thither, which should kill his neighbour unawares, and hated him not in times past; and that fleeing unto one of these cities he might live:

Namely, Bezer in the wilderness, in the plain country, of the Reubenites; and Ramoth in Gilead, of the Gadites; and Golan in Bashan, of the Manassites.

And this is the law which Moses set before the children of Israel:

These are the testimonies, and the statutes, and the judgments, which Moses spake unto the children of Israel, after they came forth out of Egypt,

On this side Jordan, in the valley over against Beth-peor, in the land of Sihon king of the Amorites, who dwelt at Heshbon, whom Moses and the children of Israel smote, after they were come forth out of Egypt: