According to the NHS website:
The National Honor Society (NHS) is the nation’s premier organization established to recognize outstanding high school students. More than just an honor roll, NHS serves to recognize those students who have demonstrated excellence in the areas of scholarship, service, leadership, and character. These characteristics have been associated with membership in the organization since its beginning in 1921.
Today, it is estimated that more than one million students participate in NHS activities. NHS chapters are found in all 50 states, the District of Columbia, Puerto Rico, many U.S. territories, and Canada. Chapter membership not only recognizes students for their accomplishments, but challenges them to develop further through active involvement in school activities and community service.