Dining at Emerson & Ruth Situated on wooded hilltop acres overlooking the Hudson River, the main tower of Castle Hotel & Spa forms the highest point in Westchester County, New York. Castle Hotel & Spa is a medieval-style structure meticulously transformed into a luxury hotel Only 25 miles north of Manhattan, Castle Hotel & Spa opened as a luxury hotel in 1997; 16 years after being designated a historic landmark.