I'm surprised BOWDOIN PARK in New York has not been mentioned. The course record is 15:29, and any mark below 16 minutes there is considered "special". It hosts 3 or so competitive invitationals where the likes of CBA compete (only one coming to mind right now, been out of the game for a while), the NY State Section 1 meet (which includes the northern suburbs of New York. Incredibly deep, whether or not there is a ton of talent at the top like Cali), the NY Federation meet, and finally the NXN regional. The course is essentially up and then down with a small hill before the finishing straight. Very easily harder than Van Cortlandt. More people have competed on Van Cortlandt probably on account of the Manhattan invitational.
This one doesn't attract many teams but the White Plains high school course is BRUTAL. It has a lot of steep up and down, but most notably it has the wall. 50m of >70% slope that sucks the life out of your legs that you have to do twice, one of which right before the final charge home. State Qualifiers is held there next year, can't wait to see that. For the record, the course record is held by a 25 minute 8k runner at Marist. 16:41.