This dissertation examines representations of interior space in twentieth-century British and Irish texts, where the question of “home” has an urgency that is particular to a century in which personal and national spaces underwent extraordinary transformation. I examine national change at the level of the interior room, where characters expressly or tacitly pursue a stable home, even as the rooms that constitute their houses are increasingly drafty, mobile, and unsettled. In novels by Virginia Woolf, Elizabeth Bowen, J.G. Farrell, Jean Rhys, Sam Selvon, Doris Lessing, and W.G. Sebald, I analyze how representations of destabilized interior spaces are mobilized on behalf of larger arguments about imperial politics in which the relatively stable framework of national identity in the nineteenth century gives way to a more dispersed and disrupted sense of Englishness in the twentieth century. The novels I read stage a conflict between the house as a secure space of the nation or national symbolic, and the house as a space unsettled by colonial encounters, war, and immigration. Political upheaval is not merely experienced in but enacted through domestic space, where the room becomes a site of national conflict and occasionally the source of military, imperial, or political power. Through their representation of unsettled interiors, these novels critique “territorial nationalism” as a key geographical construct that delineates subjectivity. In these novels, the “home” is disoriented in both its material forms (the house) and metaphorical forms (citizenship and national affiliation). In the twentieth century, changes to interior life give rise to changes in literary form. The representation of rooms as bounded but continually changing spaces works as a critique of realist form, which presupposes more stable versions of subjectivity and more stable narrative forms. These novels offer an alterative model that privileges fluidity, instability, and unsettledness. The room offers a distinctive metaphorical territory for novelists because as an enclosed but fluid space, it can simultaneously work as a metaphor for England’s unsettled national interior space, for the space of the novel, and for the interior space of the mind. Space was once considered the sphere of fixity and solidity, in contrast to time, which was conceived as boundless and unstable; in the last few decades, human geography has countered these assumptions to show that space is also a sphere of heterogeneity. The novels I read both anticipate and critique human geography by representing interior spaces as at once stable and shifting. That is, rather than present interior spaces as endlessly in flux, they show interior space as a site of tension between the desire for solidity and the reality of continuous change. These fictional rooms work to expose how spaces that are assumed to be coherent, closed, and safe are unstable, open, shifting. The breakdown of the solidity of the room is enacted through the breakdown of the stability of the realist narrative. Disorienting narrative spaces perform the disoriented space of the home; these “disorienting” formal choices take shape through shifting narrative points of view, grammatical evasiveness, digressive sentence or chapter structures, and interruptions or revisions to genre. Interior spaces are continuous with a changing social world and offer new ways of understanding how this social world is destabilized by imperial and late imperial political conditions and war in Britain, especially in relation to interior consciousness. I argue that rooms are a mechanism for demonstrating disruption and disorientation in characters’ social worlds and their subjectivity. As a metaphor, the room exposes the interrelation between disruptions to material life and to psychological life; interior space is at once a more compelling and more unstable metaphor for national and individual identity. Whereas the home was once seen as a site of seclusion, safety, or escape, these novels demonstrate that the relative stability of national interiors and local interiors give way, making everyone an exile, even at home.