Aside from Illinois (age 14) and Maryland (age 8) the law does not stipulate at what age a child can be left home alone. Mainly because age is only one factor to consider when leaving a child alone at home. Other factors include,
DO keep in mind that a parent is responsible for the child's safety and security until legal age, so if something happens while they are not home, they can be charged with a multitude of crimes depending on the circumstances.
Let me know if you have any other questions.