Set within five private acres in one of Great Falls's most coveted enclaves, 558 Innsbruck Avenue is an extraordinary custom estate where remarkable scale, enduring craftsmanship, and a waterfront setting on Arnon Lake create a residence of uncommon presence. A sweeping driveway winds through the grounds before arriving at the custom-cut-stone home. Originally constructed by master builder George Sagatov, renowned locally for estates of enduring quality, the residence spans 14,700 finished square feet, balancing grandeur with an atmosphere that remains warm, inviting, and deeply connected to its surroundings. The three-story foyer immediately establishes the architectural character of the home. Floating staircases rise through a dramatic volume exceeding 30 feet in height, framed by custom wrought-iron railings reflecting three generations of artisanship. From this central gathering point, the principal living spaces unfold with a natural progression and sense of occasion. Embassy-sized formal rooms are grand in scale and rich in millwork, harkening back to a bygone era of hand craftsmanship. A wood- and leather-paneled library offers an intimate counterpoint, opening to a private second-floor terrace overlooking Arnon Lake. The double-height great room shifts the scale toward relaxed living, with soaring coffered ceilings, a floor-to-ceiling stone fireplace, and expansive water views. At the heart of the informal living spaces, the gourmet kitchen is designed for both serious culinary pursuits and sophisticated entertaining. A generous walk-in pantry provides substantial storage, while a dedicated butler's pantry creates a discreet connection between the kitchen and dining room. Beyond, a breezeway leads to the showstopping sunroom, where a sophisticated layered ceiling draws the eye upward and walls of windows pull the landscape and water views deep into the home, creating an effortless transition between interior and exterior living. Each bedroom is conceived as a private suite complete with a full bath and walk-in closet. The lavish primary suite includes a dressing room designed in the style of a luxury boutique, with illuminated built-ins and dual islands, alongside a spa-like marble bath. A centralized upper-level retreat provides gathering space, while the third floor introduces a dedicated conference room, bunk room, separate recreation room, and flexible spaces that allow the upper level to function as a destination unto itself. The walk-out lower level transforms recreation into an experience of its own. A substantial paneled bar and step-down recreation and game rooms are arranged in Sagatov's trademark style, with soaring ceilings and abundant natural light. A state-of-the-art home theater is tucked away, while the wellness wing includes a fitness center and steam room. A cabana with its own bar area offers a more casual, pool-centric setting, connected to the sunroom above by a custom spiral staircase. Beyond the interiors, the estate's relationship with its setting becomes especially compelling. Covered porches, balconies, terraces, and patios extend the architecture into the landscape, creating numerous vantage points from which to experience tranquil Arnon Lake and the property's mature surroundings. The swimming pool and waterfront establish the rear grounds as a private retreat, with more than 200 feet of shoreline lending a serenity rarely found this close to Washington. A broad motor court and four-car garage complete a residence designed for everyday life and grand-scale entertaining with equal ease. For all its extraordinary dimensions and amenities, 558 Innsbruck Avenue is defined less by any single grand gesture than by the cumulative effect of its architecture, setting, and thoughtful sequence of spaces. Room after room, level after level, the estate reveals another layer of its character, creating a private Great Falls sanctuary where remarkable scale is balanced by uncommon intimacy.