More than 10,000 primary and secondary schools engaged in 1970 Earth Day activities. Schools joined the new environmental movement through education and practical service projects, including beach cleanups, tree planting, and recycling drives.
The figure belongs to the first Earth Day, held across the United States on April 22, 1970. K–12 coordinator Bryce Hamilton worked with major education organizations, including the National Education Association, the American Federation of Teachers, and the National Science Teachers Association, helping teachers organize local events.
The school participation was part of a much larger mobilization. An estimated 20 million Americans took part in rallies, marches, demonstrations, and teach-ins. Earth Day organizers deliberately made the event broad enough to include classrooms, community groups, labor unions, and public officials rather than limiting it to campus activists.
A common mix-up is confusing the school count with the overall attendance. The more than 10,000 figure refers to participating primary and secondary schools; it does not mean that only 10,000 people joined Earth Day. The nationwide participation estimate was roughly 20 million Americans.