Driving DirectionsFrom Advance, take Route C west 7 miles. HighlightsThis area is equally divided between forest and cropland. Facilities/features: boat ramp, primitive camping, and a permanent stream (Castor River). About This AreaGreenbrier Unit of Duck Creek Conservation Area is in southeastern Bollinger County. The Conservation Department purchased this 460-acre lowland swamp to preserve a small portion of the 2.4 million acres of hardwood bottomland swamps that once covered the southeastern part of the state.Situated between Crowleys Ridge and the Ozark Plateau, the swamp formed after the Mississippi River abandoned its channel through the region and shifted east toward Cape Girardeau.  Runoff from the Ozark hills, heavy rainfall and overflow flooding from the Castor River floods the surrounding swamp.The floodplain consisted of lowland hardwood forests of bald cypress, tupelo gum, overcup, pin oak, cherry bark and willow oaks.The area presently supports populations of turkey, deer, swamp and cottontail rabbits, otter, beaver and squirrels.Visitors to the Greenbrier Unit will find a variety of habitat, including Castor River frontage, agricultural fields and food plots, oxbows, sloughs, giant cane brakes and oak-hickory ridges. Bottomland hardwood trees have been planted on much of the area in efforts to restore some of what has been cleared in the past.