Brown Marsh Township, population 1,865, is one of fifteen townships in Bladen County, North Carolina. Brown Marsh Township is in size and is located in southern Bladen County. The Town of Clarkton, North Carolina is within Brown Marsh Township.
Brown Marsh Township is drained by Brown Marsh Swamp and a tributary, Bigfoot Swamp. All of these streams are part of the larger Waccamaw River drainage.