About Thacher Founded in 1889, The Thacher School is a coeducational boarding high school (grades 9-12) located 85 miles northwest of Los Angeles, California. The School serves academically talented students who will benefit from a rigorous college preparatory experience. The faculty and students live and work closely together in a community in which cooperation, trust, honesty, and respect are the cornerstones of school life. Together, we commit to the belief that demands in the academic classroom, when combined with those of mountains and horses, of sports and the arts, produce independent minds, strong bodies, and powerful character.