Red Hook, Dutchess County (120 acres)—In 1849 members of the Astor and Delano families, who lived on adjacent estates, commissioned German-born landscape architect Hans Jacob Ehlers to make improvements on these grounds. The classic wooded vistas, sunlit fields and thick forest were the main focus of Ehlers' vision for the property. He fashioned a series of "outdoor rooms," using stands of foliage and stone walls to break up the landscape, which includes rolling meadows, forests, and a ravine. Ehlers also created a shaded, streamside path, dubbed Poets' Walk in honor of Washington Irving and other literary figures who reputedly strolled here. (Legend has it that Irving came up with the idea for "Rip Van Winkle" here while gazing at the distant but very prominent Catskill Mountains, site of his protagonist's decades-long sleep.) Today, the park features two miles of trails through woods and rolling meadows with rustic cedar pavilions, footbridges, and benches. The park is buffered on all sides by 780 acres of private lands under conservation easements that ensure the landscape's protection from development.