Coordinates: 37°3′3″N 76°58′52″W / 37.05083°N 76.98111°W Dendron Swamp Natural Area Preserve is a Natural Area Preserve located in Sussex County, Virginia. Located along the Blackwater River and 19 acres (77,000 m2) in size, it supports a swamp full of bald cypress and tupelo. Canopy trees over 30 meters tall line the river for two miles (3 km), and the swamp shows only occasional signs of logging. Some of the larger cypresses are believed to be over 600 years old. Within the preserve is a nesting site for the great blue heron.