Some Properties Are Defined By What They Include. This One Is Defined By What Cannot Be Built Again. Officially Designated As A Horse Farm On The Town Of Riverhead's Assessment Roll, 291 Deep Hole Road Stands Apart Not By Virtue Of Size Alone — But Because The Combination It Represents Is No Longer Achievable. Current Zoning And Permitting Conditions Across Long Island's East End Have Effectively Closed The Door On New Construction Of A Residence Of This Scale On An Agriculturally Classified Parcel. What Exists Here Exists Permanently, And On Its Own Terms. The Hollenbeck-designed, Mab Custom Built Residence Commands Its 5.1 Acres With Quiet Authority. Eighteen-foot Ceilings Draw The Eye Upward Through Sun-filled Open Volumes Shaped By A Passive Solar Philosophy — Spaces That Live Generously Across All Seasons, Grounded By Mexican Terra Cotta Flooring And Anchored By Two Fireplaces. The Primary Suite Occupies Its Own World Within The Home: Angled High Ceilings, A Southern And Western Exposure Calibrated For Year-round Light, And Glass Sliders Opening To Dual Private Decks Above The Grounds. Four Bedrooms, Three And A Half Bathrooms, A Four-car Garage With Nine-foot Clearance — Every Element Scaled To The Life This Property Supports. The Equestrian Infrastructure Needs No Embellishment. A 42 X 70 Foot Morton Barn — Twelve Rooftop Skylights, Insulated Roof, Six 10 X 12 Stalls, Dedicated Tack Room — Serves Rolling, Fenced, And Gated Pastures Backed By A Natural Southern Woodland Line That Will Never Be Developed. At The Center Of The Operation: An 80 X 120 Foot Indoor Riding Arena, Purpose-built, Professional In Every Dimension, And Irreplaceable In Today's Regulatory Environment. This Is Not A Property That Competes. It Occupies A Category Of Its Own On The North Fork.