Hat Island, also known by its historic name Gedney Island, is a small private island in Possession Sound, part of Washington's Puget Sound, within Snohomish County. It lies a short ferry crossing from Everett, on the mainland, and is administered as a census-designated place. Unlike most Washington communities, Hat Island is not connected to the mainland by bridge or road; access is by private ferry or private boat, a defining feature of life there. The island's modern identity took shape in the early 1960s, when developers promoted a resort called the "Hat Island Riviera," advertising a marina, golf course, yacht club, and hotel-style amenities. The venture collapsed and went bankrupt by 1965, leaving the property owners to take matters into their own hands. They formed Hat Island Community Inc. and, over time, built a resident-managed private community around a working marina, a nine-hole golf course, and a clubhouse. Today Hat Island is an owner-governed enclave maintained by the Hat Island Community Association, which operates the 127-slip marina, the golf course, and other shared facilities. The island has a small year-round population and a considerably larger seasonal one, with homes functioning largely as vacation and second residences. Residents and guests move around the island on foot or by golf cart, and social life concentrates on the yacht club, clubhouse, and waterfront. The appeal of Hat Island is its seclusion and its outdoor setting. Beaches ring the shoreline, and the surrounding waters support clamming, crabbing, fishing, and whale watching. Golf, tennis, and pickleball round out the recreational offerings. For buyers, the island offers a rare combination: a private, ferry-dependent waterfront retreat that remains within about 15 minutes of Everett and roughly an hour's drive-plus-ferry of Seattle, with Seattle-Tacoma International Airport about 52 miles from the mainland side.