https://www.childwelfare.gov/pubpdfs/homealone.pdf
According to this very official federal document from 2013, three states have laws and the ages are 14,10,and 8 for those states.
If my kid was at a day camp, he wouldn't be home stacking firewood. It's a win for the house.
Also, he can make food for himself, can call any number of people in an emergency (including 911), and completes his daily chore list. He likes it because he gets to go fishing and has time to be alone.
Of course, if there was concern, we could call Snick's husband to hang with him.