Ohio River

Main eastern branch of the Mi i ippi, draining the west slopes of the Appal a chi an Mountains. It is formed by the junction of the Allegany and Monongahela, at Pittsburg, Pa. Thence its course is generally s.w. to its mouth at Cairo, Ill. Its main branches are, from the north, Muskingum, Scioto, Miami, and Wabash; from the south, the Kanawha, Big Sandy, Licking, Kentucky, Green, Cumber land, and Tenne ee. Its length is 1,204 m.; average discharge 158,000 cubic st. per second. It is navigable at ordinary stages of water to Pittsburg. There are falls at Louisville, which are surmounted by means of a canal and locks. Its drainage area is 201,720 sq. m. The great floods generally occur in May.