The Rockwood estate was established by Joseph Shipley in 1851 from several colonial-era farms on land that is the traditional home of the Lenape Indian Tribe of Delaware. He cultivated this land for his horticultural interests of farming and collecting specimens for his private garden establishing one of the earliest arboretums in the area. Many of his original plantings can still be found in this 170-year-old Heritage Garden. This six-acre garden surrounds Shipley’s Gothic Revival mansion, now museum, filled with the collection his family amassed over 120 years. Rockwood has been owned and operated by New Castle County since 1972.