Independent School League (New England)

The Independent School League (ISL) is composed of fifteen New England preparatory schools that compete athletically and academically. Founded in 1948, the ISL's fifteen members compete in eighteen sports in the New England Prep School Athletic Conference (NEPSAC).

Charter members of the Private School League were Belmont Hill, Brooks, Buckingham Browne & Nichols (BB&N), The Governor's Academy, Milton Academy, Noble & Greenough, St. Mark's, and Thayer. Like the Ivy League, the ISL began as a loose affiliation to promote football among academically rigorous, Northeastern schools; however, administrators formalized the league during 1948.

In 1968 Middlesex joined, and in 1972 Groton replaced Tabor – both private boarding schools in the Boston area.

In 1973 St. Sebastian's was added and in 1974 Roxbury Latin was added. The league changed its name to the 'Independent School League' in 1974.

St. Paul's, Lawrence Academy, The Rivers School and St. George's – all private boarding schools – joined during the mid-1970s.