si was the high school division of what later became the university of san francisco, but it has since split from the university and changed locations five times due to the growth of the student body and natural disaster. in the 1860s, the school built a new site, adjacent to the first, on market street in downtown san francisco. in 1880, si moved its campus to a location on van ness avenue in the heart of san francisco, and by 1883, si had become the largest jesuit school in the nation.