The Lost River Groundwater Drainage Basin in Warren County, Kentucky, is a karst drainage system encompassing 55 square miles (143 square kilometers) developed within the Mississippian St. Louis and Ste. Genevieve Limestones. Near the contact between these two formations are two bedded chert units, the Lost River Chert Bed (Elrod, 1899) within the Ste. Genevieve and the Corydon Chert Member (Woodson, 1983) of the St. Louis, which appear to be perching layers to shallow karst groundwater flow. Groundwater may be seen flowing on top of these beds in various cave streams and at swallets and springs throughout the basin. In order to compare the vertical positions of these layers to shallow karst groundwater flow, geologic structure maps of the Lost River Chert Bed and the Corydon Chert Member were prepared for the basin, along with a contour map of the water table (at or near which shallow karst groundwater flow is assumed to take place) over the same area. These surfaces were digitized, then contoured and compared using SURFACE II and DISSPLA computer graphics systems. Correlation was accepted for points where the water table is either 20 feet (6.1 meters above or below the top of the two chert layers. The water table (at baseflow conditions) was found to correlate with the Lost River Chert Bed over 42.6% of the basin, as well as 40.7% for the Corydon Member. Shallow karst groundwater flow is found to correlated with bedded chert layers over 83.3% of the study area, and therefore it is concluded that chert layers have a dominant effect on the vertical position of groundwater flow within the Lost River Groundwater Drainage Basin.