17 Hillside Avenue Steeped in rich history, this extraordinary and romantic, one of a kind property dates back to the late 1700s when it served as a homestead with a working grist mill. Set across just over 2 acres, the land features a large scenic pond, cascading waterfalls, and a tranquil stream that feeds the Saddle River. There are 2 full homes on the property and a detached 3 car garage. The main home (c.1886, 1924) offers 4 bedrooms, 2.5 bathrooms, a full spa with sauna and natural plunge pool. The main patio that meets the water’s edge. The great room exudes rustic charm with dramatic heavy beams and soaring ceilings. The second house, thoughtfully rebuilt in approx. 2017 on the original circa 1790's foundation, provides 3 bedrooms and 2 bathrooms, blending modern convenience with historical character. The former carriage house has been converted into a 3-car garage, complete with a charming studio loft and a full stone fireplace. This rare property, straddling the picturesque towns of Upper Saddle River, NJ, and Airmont, NY, offers a one-of-a-kind opportunity to own a piece of history surrounded by natural beauty and timeless craftsmanship.