In India, the country with the third largest Muslim population in the world, residential segregation along religious lines has long been of concern. Many go so far as to speak of the large-scale ‘ghettoization’ of Muslims, a trend commonly attributed to the state’s negligence towards this religious minority and prolonged histories of so-called ‘communal’ violence between religious groups. Others emphasize long-standing pattern of residential clustering in enclaves and claim that these have always been voluntary. Both the ghetto and the enclave are usually considered highly segregated spaces, though. This paper complicates such views through an in-depth engagement with the seminal ethnographic volume Muslims in Indian Cities, edited by Laurent Gayer and Christophe Jaffrelot. Based on novel quantitative estimates of religious demography, I contrast and compare the same 11 cities studied in their book – Mumbai, Ahmedabad, Jaipur, Lucknow, Aligarh, Bhopal, Hyderabad, Delhi, Cuttack, Kozhikode and Bangalore – using statistical indices of segregation. This comparison with the ethnographic ‘gold standard’ shows that the mere extent of segregation is an insufficient shortcut to the phenomenon of ghettoization: a ghetto actually need not be highly segregated and a ‘mixed area’ can be surprisingly homogenous. Consequently, I argue that one should not only distinguish between voluntary and forced clustering but also consider the wider ‘mental maps’ through which inhabitants experience, perceive and judge their city. Such mental maps specifically help to uncover historical trajectories, feelings of insecurity and the future expectations of people regarding their cities – irrespective of quantitative degrees of segregation.