just did some quick math
Nassau & Suffolk Counties combined is 2.8 million total pop.

The 4 Md. counties (Carroll, Montgomery, Baltimore, Howard) 2.3 million

I find it hard to believe that the Md. clubs are not pulling from Anne Arundel (Annapolis), Harford (bel Air) or Queen Anns (centerville) if added in Md pulling from 3.16 million

Pretty close in numbers though. But remember , just by geographical location L.I. does not pull from any other source because the city pretty much isolates it from every other place on earth, ( if you ever tried to get through it you know what I mean), where kids from the Northern Virginia and other Md. counties could make the drive, and I am sure they do