It is a non-profit organization founded in 1922 as the Nevada Interscholastic League and became affiliated with the National Federation of State High School Associations in 1939.

This list includes state championship results for recent seasons for schools competing in the highest division existing in that year.

Each of the three major categories in high school activities – academics, athletics and sportsmanship – are weighted equally, and boys and girls programs are combined in the standings table.

The NIAA honors the winning school in each classification by presenting it with a championship banner and commemorative trophy.

The NIAA considers the Award of Excellence in Academics, Athletics and Citizenship to be its top overall program.