A number of sites associated with the Trzciniec Culture, including site 52 at Obierwia, were discovered during fieldwalking in this region in 1984. The sites were situated in the dune belt on the northern flood terrace of the Omulew River. The sites at Obierwia are located almost in the middle of the current Kurpiowska Forest. The area of the Kurpiowska Plain was originally shaped as a result of the Middle Polish Glaciation (the Wartanian stage). It was then transformed during the Baltic Glaciation, when a large outwash plain with elements of earlier moraines, later interspersed with parallel valleys of medium-sized rivers and a network of smaller watercourses and bog-like oxbow lakes, was formed (Fig. 1). An exploratory survey at Obierwia was carried out in October 2000 (Fig. 2). Two trenches oriented along N-S and W-E axes and intersecting at the culmination of the elevation were established. The exploration did not uncover a cultural layer, however, numerous archaeological pit-like features were discovered (Fig. 3). 16 flint products including three tools and a fragment of a smoothed stone tool were found in the course of the excavation. Seven flint products bear signs of use or further processing (Fig. 4). Most attest that the splintering technique was used. The most interesting product was made from a splinter and retouched on one of the side edges. Based on the burnishing of the retouched edge, this artefact should be included in the category of inserts, which, next to arrowheads, constitute the most characteristic tools from the Early Bronze Age. Among 1156 fragments of pottery, there were 20 rim sherds, including two with an ornament in the form of horizontal appliqué bands, and five with holes or indentations under the rim. Most of the fragments come from the vessels of the Trzciniec Culture described by A. Gardawski as type 5 – vessels with a “tulip-shaped neck and rim, most often with a mortar-shaped body” and with a row of holes under the rim and a horizontal appliqué band. In the Younger Subboreal (Early and Middle Bronze Age), the continental, dry and warm climate prevailed in the area of the Kurpiowska Forest. Sandy soils desiccated due to the smaller amount of precipitation, and with the lowering level of the groundwater the oxbows and lakes dried out and were overgrown. The human groups of the Early Bronze Age, who penetrated into the Kurpiowska Plain in relatively high numbers, could not employ the agricultural model of economy. Based on the traces of their stay observed during the course of fieldwalking and rare excavations, it appears that they preferred the same settlement conditions as their Mesolithic and Paraneolithic predecessors. It is assumed that the Early Bronze Age settlement in Mazovia began in the first half of the second millennium BC. The settlements of the Trzciniec culture from that period appear almost exclusively in the dune belts in the valley of the Narew River, near the mouths of the Omulew, Rozoga and Szkwa Rivers, while the camps are registered in the upper parts of the river valleys. Hunting and gathering played the leading role in the economy of the groups that settled at the edge of and within the forest.