The Independent School League or ISL is a prep school athletic conference located in the Washington, D.C. metropolitan area of the United States.
It was founded in 1985.
[1] Although the ISL sponsors only girls' sports, not all fifteen ISL schools are "all-girls" schools.
The ISL sponsors ten sports: basketball, cross country, field hockey, lacrosse, soccer, softball, swimming & diving, tennis, track & field, and volleyball.
Most of these competitions are divided into two divisions, with yearly promotion and relegation between the two divisions.