Poplar Bluff, city (1990 pop. 16,996), seat of Butler co., SE Mo., in the Ozark foothills, on the low bluffs of the Black River near the Ark. line; inc. 1870. It is a trade, shipping, and medical center in a fertile farming area. Among its manufactures are transportation equipment; plastic, wood, and paper products; furniture; building materials; flour; and shoes. Nearby are Mark Twain National Forest and Wappapello Dam.