There is a growing interest in understanding and using local knowledge, resources, and stakeholders to achieve tailored and effective circular solutions in the built environment. Although the importance of clear centralised guidance and regulations are emphasised in the existing literature, there is also an emerging acknowledgement that understanding the ‘local context’ will be key to achieving tailored solutions that can effectively work in practice. However, there is a lack of discussion around the meaning and significance of ‘locality’ in terms of circularity solutions in the built environment. This discussion paper introduces space (both physical and social) and knowledge as two key aspects of ‘locality’ for enabling effective circular solutions in the built environment. Further, it argues that the cities can be seen as the locus of circular economy because of their role in localising space and knowledge. Thus, the paper enables a starting point to structure research towards an improved understanding of (i) the role of space and knowledge co-production for a circular built environment, (ii) the relevant local stakeholders, as well as (iii) city-level governance of locality in supporting a circular built environment.