USGS Topographic Quadrangle Map - The Dalles South, Oregon (Folded/Waterproof) Note - See Product Description below for how to search for and identify the correct map. Map provides detailed cartography for hikers, hunters, off-road enthusiasts and land-use professionals. Printed on waterproof/tear-resistant media from USGS 7.5 minute topographic data. Approximately 20 x 26 inches. Scale: 1:24,000 (best detail available). Contour Interval: 40 ft. Datum: NAD27 USGS Year: 1994 (most recent available). Ships folded unless 6 or more ordered.