Three sections critical to the interpretation of upper Pleistocene deposits in northern Ohio are the Titusville, Pennsylvania, site and the Garfield Heights and Mt. Gilead sites in Ohio. At Titusville, Pennsylvania, the relation of peat dated at about 40,000 yr B.P. to the Titusville till is unclear. The interpretation of early Wisconsinan glaciation at Garfield Heights, Ohio, has been based on the Garfield Heights till and a subsequently derived accretion gley, both of which overlie a truncated paleosol (Sangamonian soil?) and two formerly exposed weathered tills. Current interpretation assigns the Garfield Heights till to the Illinoian. Previous interpretations for a middle or early Wisconsinan age of the Millbrook till of north-central Ohio have been placed in question by thermoluminescence ages of 146 ± 25 ka and 124 ± 16 ka on overlying loess at Mt. Gilead, Ohio. Much of what has been called Millbrook till has been traced to areas previously mapped as Illinoian. Thus, there is no evidence to support early to middle Wisconsinan glaciation in northern Ohio and adjacent northwestern Pennsylvania. During the early to middle Wisconsinan, landscapes in Ohio may have been geomorphically unstable, and deposits from this time may be in buried valleys or may have been eroded by late Wisconsinan glaciers.