Northeastern Louisiana includes the parishes of Catahoula, Concordia, East Carroll, Franklin, LaSalle, Madison, Morehouse, Ouachita, Richland, Tensas, Union, and West Carroll. Monroe is the region's largest town. Archaeological evidence indicates that the Native American Poverty Point culture inhabited this area as early as 2000 B.C. Because the Mississippi, Black, Red, and Ouachita rivers all flow through northeastern Louisiana, some refer to the area as the “Delta Parishes.” The rivers enrich the region’s soil with their sediment, but also subject the area to periodic flooding. Perhaps because of its soil, northeastern Louisiana remains predominately rural.