Long Island National Golf Course is an 18-hole public golf course in Riverhead, New York, built in 1999 and designed by Robert Trent Jones, Jr.. It sits in the $$$$ (splurge) price range for golf in New York. The season runs Mar 1 to Nov 30. Tee times can be booked 7 days in advance. Guests are welcome.
Details like fees and seasons change, so call the course before you head out.