Joshua 4:8-9

8And the people of Israel did just as Joshua commanded and took up twelve stones out of the midst of the Jordan, according to the number of the tribes of the people of Israel, just as the Lord told Joshua. And they carried them over with them to the place where they lodged and laid them down there.

9And Joshua set up twelve stones in the midst of the Jordan, in the place where the feet of the priests bearing the ark of the covenant had stood; and they are there to this day.