I know if you go to
www.defunctparks.com and look at the past parks I think Pennsylvania had the most. In my area within an hour and a half of Knoebels I can think of around 10 parks that are no more. I'm sure there are lots more though. Within the past 20 years several parks closed down that I've been to and I'm only 24: Doodlebug Park, Rocky Glen Park, Angela Park, Magic Valley Park. All of them had coasters too even if some are small kiddie coasters.
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Parks Hit For 2000! PKD, BGW,DP,HP,PKI,HW,SFKK,SFA,GAdv,SFNE,LC,GE,QP,CDP,LP,KG,SFO,WG,GE,KW,IW,WL,