Accessibility to cultural heritage is crucial for fostering inclusive urban environments and preserving historical and cultural identities. This study addresses the gap between heritage conservation and urban accessibility with two objectives: (1) to identify tangible and intangible cultural heritage elements based on user preferences from the social media platform Foursquare, and (2) to assess the impact of accessibility on public engagement using Space Syntax analysis. The historic centres of Valencia and Alicante, Spain, were chosen as case studies for their rich cultural heritage and dynamic urban contexts. A novel urban cultural heritage (UCH) taxonomy was developed to categorise heritage elements into buildings, public spaces, elements, and events/festivities. Findings indicated that social media data offer valuable insights that complement official heritage catalogues, providing a richer understanding of cultural assets and public engagement. The results showed that higher public engagement was concentrated (1) in and around key heritage sites, (2) in heritage sites that combine cultural significance with multifunctional public use, (3) in public spaces and urban nodes that are highly accessible and well connected to the urban structure, (4) in areas where clusters of heritage elements are located close together, and (5) around sites of architectural prominence and cultural significance. This emphasised that accessibility is as important as historical significance for attracting public interest. The study suggested that improving accessibility and integrating social media data with traditional methods can enhance heritage conservation strategies and support sustainable urban development by fostering stronger identity values within cities.