Fenwick is a borough in Middlesex County, Connecticut, United States, in the town of Old Saybrook. The population was 53 at the 2020 census, making it the least populous borough in Connecticut. Most of the borough is included in the Fenwick Historic District, listed on the National Register of Historic Places. In 1995, the district included 66 contributing buildings and one other contributing site. Fenwick is set off from the town center of Old Saybrook by a large cove crossed by a causeway. It is located exactly where the Connecticut River flows into Long Island Sound, and sits on the river's west side. The town has two lighthouses, the Inner and the Outer. The Inner is at the tip of Lynde Point, Fenwick's peninsula, and the Outer is a quarter mile off shore, connected by a rough jetty. The Outer Light is the lighthouse shown on many Connecticut license plates. Fenwick Historic District The Fenwick Historic District covers an area of approximately and was added to the National Register of Historic Places in 1995. It includes 60 buildings in the center of Fenwick, as well as the Fenwick Golf Course. Architecturally, the Fenwick Historic District is composed largely of Shingle-style residences from early in the century. The Historic District comprises the bulk of the community, however some residences were built in the 1950s in a more modern style. Of the district's 60 main buildings, 17 represent examples of the Shingle style, with some others in Queen Anne or Victorian styles. Frequent features include gable-on-hip roofs that encompass side porches with minimalist wood bracing, creating a sense of heaviness characteristic of the Shingle style. Other frequently observed common architectural features include flares at the eaves of roofs, upper stories that overhang lower stories, and pent roofs over windows and doors. All of the three are typified in St. Mary's-By-the-Sea, a 1 and 1/2 story church building at 30 Agawam Avenue, designed by Francis Goodwin and built in 1883. In the late 1800s The Fenwick Golf Course was created from several empty lots in the center of the district and is the site of the Stephen Potter Cup. The 9-hole golf course has changed layouts on several occasions, with the most recent re-design in the 1930s following acquisition of the course by the British manufacturer Armitage Shanks. Geography Fenwick is in the southeast corner of Middlesex County and is bordered to the