During December 2011 a field survey of the area of the construction of the new bypass of the City of Zagreb was conducted. In the western part of Zagreb County, between junctions Pojatno and Horvati, section I is located, while in the eastern part, between junctions Ivanić-Grad and Sveti Ivan Zelina, the route of the section III was surveyed , and a number of new, previously unknown sites, were noted. A total of 41archaeological sites were observed on the first , and 19 sites on the second section. Most of the sites can be dated to the Middle Ages, although some finds have been recorded which can be dated to Prehistory and Antiquity. Within section I nine prehistoric and two ancient sites have been found, and within section III four prehistoric and six ancient ones. Only few of these locations have already been known, those beeing the sites located on the banks of the Sava River, near Zaprešić. Although finds from the Middle Ages prevail, it can be assumed that the number of ancient and prehistoric sites will be significantly increased after the rescue exavations, which will determine the exact extent and type of sites, as well as a period to which each site can be dated with much greater precision. Based on the surface finds, some sites, such as the one in the vicinity of the Lužnica castle near Zaprešić, show the traces of population presence over a longer period; this is hardly surprising given their very favorable position next to river communications, the importance of which they retained to this day. The valley of the Sava River in the vicinity of Zaprešić is already known as a place with the considerable number of ancient sites, but recent surveys have shown a dense population throughout the Middle Ages, as well as the existence of prehistoric settlements and a large number of new sites that have been observed on the hilly area on the slopes of the Samobor hills. We should specially point out new sites from all periods located on the section III between Sveti Ivan Zelina and Ivanić-Grad, since this region is relatively poorly explored.