Settlement and Neigboorhoods Centers (SNC) offer a local reception, animation, activities and social services. Through their history and their partnership affiliations, they are recognized as stakeholders social life animation, family policies and child/youth animation. For the past ten years or so, SNC have also positioned themselves as stakeholders in “well aging" and public health for the elderly population. This thesis proposes a reflection on the place of SNC as local gerontological stakeholders in a context of evolution of social action on ageing illustrated inter alia by the Law on the adaptation of society to ageing (2015), and in the face of the demographic challenge of an ageing population. To do this, it is necessary to question the action of SNC on this public as well as the stakes of its inclusion in the gerontological landscape. Our analysis is built on several scales ranging from the consideration of Well-aging in a SNC to that for SNC, as a federated network. To define the role of SNC as stakeholders of Well-aging in territories, it is also necessary to understand the impact of their actions on populations, as well as the territorial dimension of this impact. To do this, we question, among other things, the notion of "local action". Finally, the role of SNC as stakeholders in the field of Aging is also understood by the way other stakeholder actors in that field view them. The results presented are based on different qualitative and quantitative methods (interviews, questionnaires,observations, etc.) implemented as part of the I-CARE project carried out by the Union Régionale des Centres Sociaux des Pays de la Loire, which encompases this research through a CIFRE system