Abstract: The basin fill geometries of the Paleocene-Early Eocene units of the Orhaniye-Güvenç region (NW Ankara) is studied using stratigraphic sections. All over the study area, nonfossiliferous Uzunçarşı group overlies with a slight angular unconformity the late Maestrichtian aged Dikmendede formation that passes laterally and vertically to Kuşkonan formation. Uzunçarşı group, which is divided in Lülük, Gökdere and Sarıbeyler formations, plays an important role in the understanding of the Paleocene tectonics and the paleogeograpy of the reg ion.Lülük formation, which is only deposited in the central parts of the studied region, is made-up of the proximal to mid-alluvial fansediments. Gökdere formation sediments, wJiich cover wider areas, show braided river deposits characteristics. This formation is notdeposited in`the NE and S of the area. Sarıbeyler formation is the most extensive formation of the Uzunçarşı group and is composedof lake deposits in the NE and an alternation of lake and fluvial deposits in the SW. Sarıbeyler formation is overlain by a thin butareally extensive unit containing mainly volcanic cobbles, which is overlain by Middle Eocene shallow marine carbonate deposits. Paleocurrent measurements, lithofacies characteristics and distribution of the Uzunçarşı group elastics indicate a closeby S-SE source area. Therefore, Paleocene - Early Eocene sediments of Orhaniye - Güvenç region is not a northward continuation of Tuzgölü basin; but, form the continental fills of a tectonically controlled smaller basin.