They raised over him a great heap of stones, to this day; and Yahweh turned from the fierceness of his anger. Therefore the name of that place was called "The valley of Achor" to this day.
The heap of stones the people raised over Achan, his family, and his possessions (Joshua 7:26) memorialized this act of rebellion for the Israelites and their children (cf. Joshua 8:29; 2 Samuel 18:17). They named the valley in which the execution took place "Achor" (lit. troubling or disaster) as a further reminder (cf. Hosea 2:15; Isaiah 65:10). Note the wordplay with Achan’s name.