Most states do not have laws to guide families on when their child is old enough to be left alone at home for any amount of time. Instead, the decision is left to the family. When determining readiness, parents should consider their child’s feelings and have a plan in place, according to the American Academy of Pediatrics’ (AAP’s) parenting book, Caring for Your School Age Child. Until about age 11 or 12, most children are not ready to handle emergencies. The AAP advises parents to find structured supervision for most children until this point.
http://aapnews.aappublications.org/content/33/2/31.5.full.pdf