The girls private school league is MAGHL. The three strongest teams in recent years are Georgetown Visitation, Stone Ridge, and SJC. Other schools in the league: Holy Child, Holton, AHC, Spalding, Ryken, Bryn Mawr, Bishop O’Connell (new last winter), and NCS (new this winter). Although the structure of the league changes somewhat from year to year the current format is that each school has one team playing in either the upper or lower division. Talent ebbs and flows from year to year given that most of these schools are small and that this area is not known as a powerhouse for hockey generally. Also some of these schools are academically demanding and the hurdle for admissions is high (ie schools aren’t exactly “recruiting” for girls ice hockey). The WCAC schools also have their girls teams play in a sort of WCAC “playoff” in additional to their MAGHL schedules.
There’s also another league organized by geography that is made up of players who attend public and private schools that do not have teams. I don’t remember what the league is called but you can find it on the same site as the MAGHL. I believe both leagues are loosely sponsored by the Caps.