The widespread proliferation of electronic gambling machines and improvements to their design have contributed to rising levels of gambling-related harm including harms associated with addictive behaviour and other impacts on health and wellbeing. Research into their addictive potential has focused mainly on the interface between gamblers and the machines themselves. We shift the focus onto the spatial contexts, the rooms and the venues, in which gambling machines are positioned. By examining a series of common layouts we identify the division of venues into two main areas: one for the main social activities of the venue (the “main hall”) and the other a partitioned area (the “annex”) in which gambling machines are tightly clumped in ways that discourage social interaction. Other features of the annex that encourage uninterrupted and solitary play include the absence of tables to socialize around, dimmed lighting and entry pathways that minimize scrutiny. We argue that these features promote a style of play more oriented towards heavy and problematic gambling. We also explore explanations for the nature of these annexes and discuss implications for public health.