3497 BULL RUN MOUNTAIN Road UNICORN ALERT! Freedom! No HOA! Custom French Colonial "castle" with exquisite architecture, stone masonry, and a Turn-Key Apartment over the garage with private exterior entry! Brand new roof! Serene setting nestled in the foothills of the Bull Run Mountains surrounded by olde growth hardwoods and aboundant wildlife. This sophisticated estate offers a singular opportunity to claim a luxury retreat on nearly five private acres in The Plains, an exclusive area of Fauquier County. This is not merely a home; it is an experience designed for grand living, dedicated work, and quiet repose. Dramatically designed floorplan boasts cathedral ceilings and soothing natural light throughout. The enormous gourmet kitchen is a true workspace, built for function with custom elements, including a built-in 6-burner Wolf stove and high-end commercial grade stainless steel appliances. The huge kitchen island is equipped with a functional salad sink, making it a true chef's dream. An immense Walk-In Pantry provides endless storage and easy access. The incredible two-story Great Room takes center stage, boasting soaring ceilings, an upstairs overlook, and a dramatic, floor-to-ceiling stone fireplace perfect for memorable entertaining. Finally, retreat to the luxurious main-level Primary Suite, which provides a peaceful escape complete with a sitting area, a second, inviting wood-burning fireplace, and a generous walk-in closet. The primary bath is expansive, featuring a soaking tub and double sinks. Ascend the staircase to the thoughtful upper level. To the right sits a massive private bedroom with a full bathroom next door. To the left, a layout built for flexibility; two additional bedrooms, a flexible bonus/flex room, and the crowning jewel: a fully finished Au Pair Suite with its own private exterior entrance, sitting conveniently above the garage. This home features ample parking including a two-car side-load garage connected to the home via a massive and breathtaking breezeway to the convenient side entrance, ushering you into a functional mudroom and main-level laundry space. The private apartment offers unparalleled potential for guests or family. Adding significant living space, the walk-out lower level was finished in 2025 to the highest standards. It features a sprawling, open recreation room (currently set up for media use) with striking built-ins, a wine fridge, and endless open space for fitness or play. This level includes a large private entrance bedroom with a true walk-out and direct access to a rough-in bathroom. An additional unfinished storage area ensures you have utility and storage space for all your needs. The exterior is defined by incredible hardscaping throughout the entire backyard and front yard. From the main house, step out onto the expansive patio, centered around an immense built-in fire pit and beautiful stone retaining walls. The acreage offers true country living possibilities with a huge, flat side yard, a chicken coop, and an adjoining running shed-perfect for your horses, pets, or passion for hobby farming. Stunning private views surround this meticulous estate.