The Wabash Valley is a region with parts in both Illinois and Indiana. It is named for the Wabash River and spans the middle to the middle-lower portion of the river and is centered at Terre Haute, Indiana. The term Wabash Valley is frequently used in local media.

Counties in the Wabash Valley include Vigo, Clay, Sullivan, Vermillion, Parke, Greene, Putnam, Owen, Knox, Daviess, Martin, and Fountain counties in Indiana. The Illinois portion consists of Clark, Edgar, Crawford, Jasper, Cumberland, Coles, and Douglas counties. It also may or may not include, depending on who you talk to, Monroe, Montgomery, Tippecanoe, and Warren counties in Indiana. Lawrence, Richland, Vermillion, Champaign, and Effingham counties in Illinois.

Geography of Illinois | Geography of Indiana