Belvidere High School is located in at 1500 East Avenue, Belvidere, Illinois in Boone County. The school is perhaps most notable for the deaths of 13 students and staff on the afternoon of April 21, 1967 when an F4 tornado struck the school as part of a massive tornado outbreak in the Midwest.It is the sixth worse loss of life at an American school as a result of tornadoes, and the worst since 1955.