Joshua 4:8-9

8So the Israelites did as Joshua commanded them. They took twelve stones from the middle of the Jordan, according to the number of the tribes of the Israelites, as the Lord had told Joshua; and they carried them over with them to their camp, where they put them down.

9Joshua set up the twelve stones that had been in the middle of the Jordan at the spot where the priests who carried the ark of the covenant had stood. And they are there to this day.