Space is not merely an inert fact of nature, or a simple backdrop to history. It is, rather, a socially constructed set of meanings that are attached to the world around us – in place-names, in stereotypes and values (e.g. ‘rough’ neighbourhoods and ‘desirable locations’), and the psychological resonances of different spatial concepts (e.g. the meanings suggested by ‘cottage,’ ‘mansion’ and ‘cave’). Supernatural antagonists contribute to these layers of meaning, producing haunted spaces and territories where trespassers meet gruesome ends. This chapter looks at the production of monstrous space in Irish literature, leaning particularly on Michel Foucault’s understanding of the ‘heterotopia’ (a space of crisis, containing that which cannot be spatially ordered according to the dominant ideology of the society that produces them), and Gaston Bachelard’s categorisation of fear into ‘Fear in the Attic’ (transitory, insubstantial) and ‘Fear in the Cellar’ (enduring, resistant to rationalisation).