Introducing the "Crown Jewel" of sought-after and highly desired Summerfield Lane - available for the first time since the sub-division was created over 40 years ago. Ideally located south of the highway, this offering is just minutes to ocean beaches and within close proximity to beloved Milk Pail and Fairview Farm stands. Tucked away from main thoroughfares, this peaceful cul-de-sac has quietly evolved into one of the Hamptons' most exclusive enclaves, with recent land trades and new construction confirming its prestige. Set at the very end of the lane, 161 Summerfield is the finest offering of them all. Sited on an oversized 1.03 acre parcel with private access via an easement, the property enjoys the serenity of backing 19 acres of agricultural reserve - currently home to the bucolic Topping Horse Farm and protected from future development. Favorable pre-existing setbacks allow for this unique new development program including a proposed 9,000 +/- square foot new construction residence, by architect Will Minnear and developer/builder Michael Frank. The proposed modern construction includes 8 bedrooms, 10 baths, pool, spa, expansive outdoor living areas, and the finest finishes throughout. The generous lot allows for multiple accessory structures including a pool house and a north-south facing tennis court or padel/pickleball if desired. There is simply no other offering on the market that combines this caliber of location, acreage, privacy, and scale - south of the highway, on a quiet cul-de-sac, with forever-protected views and space for a full program residence - at this price point. Available as a pre-construction new build or as-is, with the existing dwelling; 161 Summerfield Lane uniquely presents as one of the premier development opportunities available in the Hamptons.