Financial troubles forced the school to close in 1901. The building was taken over by the city and became the home of Ontario High School (now Chaffey High School). In 1906 the Chaffey endowment was legally separated from USC and reorganized to benefit the newly created Chaffey Union High School District. When Ontario High school opened to students from Upland in 1911, its present name was adopted. In 1916, the Chaffey Junior College of Agriculture was added as a postgraduate department to the high school. The school's buildings were renovated and additional buildings added during the New Deal.