The North-Western Pyrenees offers a remarkable archaeological potential for the Neolithic period in a geographical key sector of Western Europe, between the Atlantic Ocean and the Pyrenean mountains, allowing natural passages to the Iberian Peninsula. However, the region remains for a long time, outside of the major fields of research, leading to its regular absence from national summaries. Considering megalithism as a gateway, we developed since 2015 a Collective Research Project (PCR) on this theme. The objective is, through the implementation of multi-method and multi-scalar approaches, to improve the understanding of regional megalithism, in its forms, its symbolism and its chronology, but also to place its emergence and its development on a more global scale, allowing to improve our understanding of the Neolithic and recent Protohistory of the north-western Pyrenees. Under the name of Pierre d'Uzès, the dolmen of Peyre Dusets is mentioned on the cadastral maps of Lourdes (1812) and Loubajac (1813) in which it also appears as a boundary marker between the two municipalities. In an article published in 1876 by E. Dufourcet, the first excavation was described and a first survey proposed. If the dolmen is named several times after, it seems that no other excavations have been achieved. When we resumed the study of this monument, it was possible to observe a megalithic chamber composed of four monoliths including a cover table (dalle de couverture) and three orthostats, one of them can be interpreted as the bedside slab (dalle de chevet), facing the East. The four slabs are all a "Cauterets" type granite. They must have the same origin, and were probably borrowed from the Mindel moraine which outcrops to the south of the site. The architectural and geological studies, as well as a geophysical survey of the monument (electrical map and tomography), raised questions about the architecture of the chamber, its placement and the composition of the tumulus. A survey operation was realized in 2019 to answer these questions. As part of our work, where we favor a "diagnostic" type approach that is minimally invasive and adapted to our problems, we have installed three surveys on the Peyre Dusets site. Because of the last excavation, we were not able to document the sepulchral levels. Nevertheless, we observed that the space inside the chamber seems to have been slightly over-deepened, forming an elongated hollow in the direction of the length of the chamber. The excavation also provides details on the conditions of installation of the monoliths, by demonstrating that the blocks n°2 and n°3 are in place and that they effectively constitute a bedside, observed in its entirety and an orthostat. The orthostat is simply installed on the local clay substrate, while the bedside is implanted in a pit dug in this substrate. This wedging pit is composed of a double filling. The lower part is made up of a dense assembly of stones of different natures (schist, granite and sandstone) and a few elements of almost exclusively yellow kneaded clay. The upper part includes balls of yellow and white clay clearly visible during excavation with an average diameter of 8 to 10 cm and a few scattered stones. The dating carried out in this survey places the construction of the monument in the recent Neolithic period (4735 ± 30 BP) and several clues suggest that the bedside was first a menhir erected prior to this date. We can underline that this date is completely consistent with the known data for this type of monument in the area. During the excavation of the bedside wedging pit, an original discovery was made : a shale slab with a particular shape. By the general appearance of the plate and the archaeological context of its discovery, everything suggests that it may be a stele with an anthropomorphic silhouette. The excavation of the tumulus revealed the presence of a structure built exclusively with dirt and preserved over nearly 1.80 m. The construction of this mound is based on a massive dirt technique. The preparation of the ground, the implementation of a foundation layer and the finely prepared character of the materials, underline the investment given to the development of this tumulus. These results, placed in a more global vision, contribute to the renewal of the problematics linked to the megalithism and give to our region, which has remained away from the major centers of research, another point of view on the neolithic societies. Beyond the discovery of this stele which appears as a first-rate element echoing prestigious sites of Western European megalithism, the importance of the earthwork, the care and the investment brought to the construction of the monument, contribute to a renewed image of megalithism and subsequently of the Neolithic in our region. Thus, until recently, the vision shared and transcribed by a bibliography, reflecting more a state of research and its historiography than a historical reality, willingly depicted a territory provided with simple dolmens with a latest chronology, crossed by pastors organized in small transhumant groups, away from everything and (especially) from the socio-economic phenomena playing out elsewhere at the same time. Recent works on West Pyrenean megalithism, whether it falls within the framework of programmed archeology as here with the dolmen of Peyre Dusets and more broadly our PCR, or within the framework of preventive excavations as on the site of the CM10 in Lannemezan, offer a vision quite far from this « image d’Épinal ». They all tend to show that the construction of monuments in the region is based on strong technical and symbolic systems, that lead to major changes in the forms of the relief and the soil cover on which they are installed, all in dynamics completely synchronous with those in play in the rest of Western Europe.