Pretty much anyone 16 and older can hunt big game alone in the United States, but many states allow pre-teens to hunt big game alone, not just rabbits and squirrels and the like. As list maintainer Outdoor Empire notes, "Generally it's recommended to be around 10 years of age to understand everything taught in the course." The states allowing pre-teens to hunt big game alone are Alabama, Alaska, Arizona, Arkansas, California, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Louisiana, Mississippi, Missouri, New Mexico, Oklahoma, Tennessee, Texas, Vermont, Washington, and Wisconsin.
A couple of commenters expressed surprise that many middle schoolers in the US take hunting safety courses. This is why.
Image: Map created at mapchart.net using data from Outdoor Empire