The Teays River was an important pre-glacial river that drained much of the area now drained by the Ohio River, and more. Traces of the Teays across northern Ohio and Indiana are represented by a network of rivervalleys eroded into Ordovician strata during the Devonian.

The Teays River was a north- to northwest-flowing river prior to the Pleistocene (Ice Ages), emptying into the shallow seas that often covered the center of North America, during the Ordovician and Devonian periods and again in the Cretaceous. The river was dissected and largely wiped away by advancing glaciers and meltwater from glaciers. The Teays flowed through southwest West Virginia, between Kentucky and Ohio, and northwest across Ohio (see image of former course and tributaries). Massive continental ice sheets began to cover large parts of Ohio and other states downstream (west) of Ohio between 2.5 and 3 million years ago. Their presence caused lakes to form along the Teays and associated rivers. Overflow of these lakes into nearby, lower valley caused large floods and new rivers to form. These rivers include the Ohio and Scioto rivers, which are associated with the most direct evidence of the Teays River.



Visual remains of the Teays River include large valleys containing only small streams. The valleys can be seen on aerial and satellite images (see aerial perspective image in this page). However, short segments of the valleys are occupied by the Ohio and Scioto rivers. The Scioto River flows through the valley in the opposite direction (south) taken by the Teays River (north).