The Long Island Greenbelt Trail Conference has the Nassau-Suffolk Trail that goes 19.8 miles south to Merrick Rd. White blazes. Connects to Walt Whitman Trail to Route 110.
There is! It's a cross-island tail (N-S) and it's almost 20 miles. (https://www.hikingproject.com/trail/7017703/nassau-suffolk-trail)
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