Numbers 33:37-41

37Leaving Kadesh, they camped at Mount Hor on the border of the land of Edom.

38Aaron the kohen went up Mount Hor at Adonai’s command and died there, in the fortieth year since the departure of Bnei-Yisrael from the land of Egypt, on the first day of the fifth month.

39Aaron was 123 years old when he died on Mount Hor.

40The Canaanite king of Arad, who was living in the Negev in the territory of Canaan, heard of the coming of Bnei-Yisrael.

41They departed from Mount Hor and camped at Zalmonah.