Camping Western NY: National membership in highly rated RV resorts across North America! Call: (877) 850-7972 to schedule a visit today. Allegany Mountain Resort at Rainbow Lake is located in Western New York State's Allegany Mountain Region near Ellicottville, New York. The Resort spans 310 acres of breathtaking countryside with camping that surrounds the entire majestic 70 acre Rainbow Lake. This setting truly separates us from all other camping resorts. We are just 10 minutes from Ellicottville, (the village of festivals). Ellicottville has some of the finest festivals in the country and it is also the home of Holiday Valley Ski Resort and the Sky High Adventure Park.