Deuteronomy 34:5-8

And Moses the servant of the LORD died there in Moab, as the LORD had said. He buried him in Moab, in the valley opposite Beth Peor, but to this day no one knows where his grave is. Moses was a hundred and twenty years old when he died, yet his eyes were not weak nor his strength gone. The Israelites grieved for Moses in the plains of Moab thirty days, until the time of weeping and mourning was over.