Mark T. Sheehan High School is a public high school located at 142 Hope Hill Road, Wallingford, Connecticut. It is part of the Wallingford Public School System, and one of two public high schools in Wallingford, Lyman Hall High School being the other.AcademicsMark T. Sheehan High School offers Advanced Placement courses in subjects including biology, calculus, chemistry, English language, English literature, environmental science, European history, French, German, music theory, physics, psychology, Spanish, statistics, studio art, United States government, and United States history.