Plum Orchard 30°51′21″N 81°27′55″W / 30.855933°N 81.465238°W / 30.855933; -81.465238 is an estate located in the middle of the western shore of Cumberland Island, Georgia. The estate and surrounding area are listed on the National Register of Historic Places.
Designed by Peabody and Stearns for George Lauder Carnegie, it was formally dedicated on October 6, 1898. Peabody and Stearns also designed various additions to the mansion in the several following years, probably in 1906.
After George Lauder Carnegie died, his widow, Margaret Copley Thaw, remarried and moved to Africa. Most of the original furnishings were sold, and furniture from Dungenes were brought in to furnish the house. The house was then occupied by the Johnston family, from Nancy Trovillo Carnegie Heaver/Johnston's branch of the family.
The estate is now part of Cumberland Island National Seashore.
The mansion includes a rare squash tennis court.