It is still unclear why residents define certain geographical areas as their neighbourhoods, and this lack of clarity has a profound impact on urban decision-making. The aim of this research has been to develop a conceptual model for self-defined neighbourhoods. I conducted a mental mapping activity with 15 residents from Dublin 8 in Ireland representing different sociodemographic characteristics, housing typologies and duration of residency. Dublin 8 is a postal code area in the inner city of Dublin chosen for its urban and social diversity. In 1:1 meetings which lasted two hours, I asked each resident to rate their neighbourhood satisfaction and draw a memory map of the area that came to mind when they gave their opinions followed by deep discussions for the reasons. While theories define a neighbourhood as the area reachable within 15 minutes walk in all directions from home, the research revealed that residents perceive their neighbourhoods as a sector of the area they walk, with their home often situated at the edge rather than the center. This sector can range from a single street to a 20 minute walk from their home and can be an area or a network of streets. The research helped in identifying some of the factors that shape self-defined neighbourhoods and developing a conceptual model to represent them. This can help in predicting the area that a resident will consider as their neighbourhood and in turn narrowing the gap between neighbourhood design and user experience.