The Fabius River is a scenic waterway flowing through northeastern Missouri and into Illinois, consisting of three main branches: the North Fabius, Middle Fabius, and South Fabius rivers. These rivers run in parallel courses southeasterly across northeastern Missouri before coming together. The North and Middle Fabius rivers merge in southeastern Lewis County, flowing about 8.9 miles before joining with the South Fabius in northeastern Marion County to form the main Fabius River. The Fabius River then flows approximately 3.5 miles before reaching its confluence with the Mississippi River near River Mile 323. The watershed offers diverse fishing opportunities with numerous pools, riffles, and extensive woody cover providing excellent fish habitat, particularly in the South and Middle Fabius branches which remain largely unaltered and maintain excellent forest buffers along their banks.