Trinity High School is a Roman Catholic college preparatory high school for girls located in River Forest, a neighborhood in Chicago, Illinois. Located in the Roman Catholic Archdiocese of Chicago, it was founded in 1918 by members of the Sinsinawa Dominican Sisters. Originally the school was built on the grounds of Rosary College, which is now Dominican University, but in 1926 the campus was relocated a few blocks away from the original site. Today, Trinity High School has an enrollment of 500 young women divided among four grade levels. Trinity students come from 45 zip codes and 144 different grade schools.