Istanbul in the mid-nineteenth century had a diverse population and a dynamic urban environment. Houses are significant components of this complex urban space. This study investigates the mid-nineteenth century Istanbul houses based on the information retrieved from the newspaper advertisements of two Ottoman Turkish newspapers in 1840-67. These houses belong mostly to the Muslim population of the mid-low and upper socio-economic classes. The survey showed the common and distinctive features of the houses and discussed aspects like price, spatial organization, household and everyday practices. Boundaries and thresholds inside and around these houses were also the themes highlighted for interpreting variations in their spatial organizations.