Welwyn Preserve County Park is a 204-acre public nature reserve in Glen Cove, on the North Shore of Long Island in the U.S. state of New York. Welwyn Preserve was originally Welwyn Estate, the estate of the industrialist Harold I. Pratt. The main house, Welwyn, was one of the Gold Coast Mansions.
Nature wise, there are more than 100 species of birds, a variety of small native mammals, reptiles and amphibians inhabit the preserve's grounds.
The preserve also plays host to the Holocaust Memorial & Educational Center, which offers exhibits and other educational programs.