Urban wars represent one – perhaps the – phenomenon in which war and cities take particular form in and through each other. With the epistemics of this reciprocal relationship being less studied, this article brings together the discourses on urban war and military interoperability respectively. Both discourses emphasise the question of knowledge. A shared geographic knowledge held by the service branches involved in a joint operation is considered key for interoperability to arise. In the urban wars discourse, the need and difficulty of ‘knowing’ the urban are stressed. However, we know less about whether military services involved in a joint urban operation produce distinct geographic knowledges and, if so, with what effects. With inspiration from critical scholarship on military geographies and from works on the history and geography of knowledge, this article develops a conceptual framework to target the mutually constitutive relationship between military epistemics and urban space in urban war. In it, I make a twofold argument, illustrated with the help of empirical examples from two Israeli joint urban military operations. First, the type of geographic knowledge that military ground and air forces produce as they seek to ‘make known’ particular urban spaces differs due to the services' distinct situatedness and relative distance to the urban environment. The produced types of military geographic knowledge, moreover, do not imply different perspectives on the urban as a pre-existing entity as much as they bring – in distinct fashions – the urban into being.