Canisius High School is a Catholic, private college-preparatory school for young men run by the USA Northeast Province of the Society of Jesus in Buffalo, New York, United States, just north of the Delaware Avenue Historic District. Founded in 1870, the school has historical ties to Canisius College. Canisius operates independently from the New York State guidelines established by the Board of Regents. It has the largest high school student population among private schools in Western New York.