Our School Where Our Graduates Have Gone To College Our Community Take a Tour     Mountain Valley High School opened in September 1989, the result of a merger between Rumford and Mexico high schools and is accredited by The New England Association of Secondary Schools and Colleges.   An experienced staff provides a broad and rich academic program; pre-vocational, business, and college prep with a total enrollment in grades 9-12 of 615 students.   There are advanced placement courses in English, U.S. History, Biology, Chemistry, Physics, and Calculus.   Honors Courses are offered in Algebra II, Geometry, Pre-Calculus, Biology,   Chemistry , Physics, and English. 2007-08 Enrollment 579 Size of Faculty 64 Senior Class Size 147 Class ranking: GPA is determinded by multiplying final grade in course, times course credit, then dividing by total credits.