Keystone National High School is a private correspondence and online distance high school based in Pennsylvania, United States. Students can earn their high school diploma at Keystone or take courses to supplement another high school or homeschool program. The school's first courses were introduced in 1974 as part of the Learning and Evaluation Center. Keystone took its current name and became a major part of the homeschool market in 1994. Over 200,000 have enrolled in Keystone's educational programs. The current enrollment is 10,000+ students.