Big Spring Bog Natural Area Preserve is a 50-acre (20 ha) Natural Area Preserve located in Grayson County, Virginia. The terrain is hilly, and within its borders is Chestnut Creek, a tributary of the New River. The preserve features a rare wetland known as a "cranberry glade". The preserve is owned and maintained by the Virginia Department of Conservation and Recreation, and is open to public visitation only through prior arrangement with a state-employed land steward.