text: Member and affiliate associations Over 19,500 high schools belong to associations that are members of the NFHS. Most high schools, whether public or private, belong to their state's high school association; in turn, each state association belongs to the NFHS. However, in states that have separate associations for public and non-public high schools, only the public-school bodies are full NFHS members.
  For example, the Texas University Interscholastic League (public schools, with non-public schools generally not allowed) is a full member; the largest association governing non-public schools, the Texas Association of Private and Parochial Schools, is an affiliate member, while other governing bodies are not NFHS members at any level. Similarly, the Virginia High School League, open only to public schools, is a full member, the state's largest association for non-public schools is an affiliate member, and other governing bodies are not members at all.
  The case in Mississippi is slightly different; the body governing public schools is a full member, while the body governing private schools is not an NFHS member at any level. In the state of Alabama, the public schools and a handful of private schools compete in the AHSAA (Alabama High School Athletic Association) which is a full member of the NFHS. The majority of private schools in the state are members of the AISA (Alabama Independent School Association) a non-member that uses NFHS rules. The AHSAA will not allow its members to play AISA schools but the AISA schools do compete with public and private schools outside of Alabama.