55 acres in the heart of Boulder County - conservation protected, never to be subdivided, never to be replicated. 11,791 finished square feet of award-winning architecture inspired by I.M. Pei and Frank Lloyd Wright, sitting on a landscape so vast and so private that the rest of Boulder County feels like a rumor. Inside, soaring cathedral ceilings with dramatic exposed beams and a wall of windows pull panoramic views right into your living room. A striking 360-degree glass fireplace anchors the living space, while custom cherry, walnut, and maple millwork from Kamtz Custom Cabinetry adds warmth and craftsmanship throughout. The primary suite is a private retreat with a spa bath, soaking tub, and dedicated spa room opening to a secluded courtyard. The garden level includes a spacious family room with fireplace and wet bar, a 144-bottle wine cellar, dedicated home theater with retractable screen and sound-dampened walls, four additional bedrooms - three en suite - and a 1,000-square-foot climate-controlled flex space ideal for a workshop, studio, or collector's garage. Radiant in-floor heat, four AC zones, a whole-home Generac generator, heated three-car garage, and additional two-car garage round out a home that thinks of everything. Outside, a year-round pond, extensive limestone hardscaping, protected courtyard, and unobstructed mountain views define this estate. Featured in 5280, Luxe Magazine, and multiple design books, the home has earned Colorado Homes & Lifestyles Home of the Year along with multiple CARE and BAR awards. Located just 15 minutes from Rocky Mountain Metro's private jet centers and minutes from Boulder's biotech corridor, downtown, and CU. An optional adjoining 156-acre irrigated parcel with senior water rights is also available, bringing the total footprint to nearly 240 acres. This is not a house. This is a holding. The biggest, most private, most unrepeatable estate in Boulder County. And it's available right now.