Lake Tight was a vast but short-lived glacial lake in the early Pleistocene that spread across parts of present-day Ohio, Kentucky, and West Virginia after advancing ice blocked the ancient Teays River near Chillicothe, Ohio. Named for geologist William G. Tight, it is central to understanding how the older Teays drainage system was disrupted. Long studied and repeatedly remeasured, the lake is now thought to have been much larger than early estimates suggested, with its boundaries supported by geologic and topographic evidence including Minford Silt deposits. Its overflow reshaped regional drainage, carving new channels and helping create the modern Ohio River basin.