Which entity has the most influence over rules concerning homeschooling?

In the United States, the entity with the most influence over rules concerning homeschooling is the individual state. While the federal government has some involvement (primarily through requirements related to disability services and certain reporting standards), each state sets its own specific regulations regarding homeschooling, including curriculum requirements, testing, notification procedures, and teacher qualifications (or lack thereof). Therefore, the level of regulation and the specific rules vary significantly from state to state.