Numbers 33:37

35They traveled from Abronah, and encamped in Ezion Geber.

36They traveled from Ezion Geber, and encamped at Kadesh in the wilderness of Zin.

37They traveled from Kadesh, and encamped in Mount Hor, in the edge of the land of Edom.

38Aaron the priest went up into Mount Hor at the commandment of the LORD and died there, in the fortieth year after the children of Israel had come out of the land of Egypt, in the fifth month, on the first day of the month.

39Aaron was one hundred twenty-three years old when he died in Mount Hor.