From 1903 until the end of the 1969 school year the students of the communities of San Dimas and La Verne attended Bonita High School. In 1959, Bonita High School campus on Damien Ave was sold to Catholic Church and the new high school campus was opened on D Street. By the end of the decade, overcrowding and the growing community of San Dimas resulted in the opening of a new high school, San Dimas High.
The first principal of San Dimas, Louis Rosen, said, "The communities of La Verne and San Dimas have given an unusual amount of support, win or lose, over the past fifty years. Football games in particular have produced what the press has often referred to as the typical Bonita fan. He comes at 4:00 p.m. in the afternoon to an 8:00 p.m. game with blankets, chicken, and a great deal of enthusiasm. The typical Bonita fan has now become the typical Bonita -San Dimas fan. The communities of San Dimas and La Verne each have a high school of their own with which to identify."