Big Black River is a river in the U.S. state of Mississippi and a tributary of the Mississippi River. Its origin (region:US-MS&title=Big+Black+River+source 33°41′40″N 89°07′59″W) is in Webster County near the town of Eupora in the north central part of the state. From there it flows 330 miles (530 km) in a generally southwest direction until it ...