This article looks at boundaries as shared points of conflict and sociality in rural Sicily where the mafia and their opponents (‘antimafia’ cooperatives) have lately been at loggerheads. My focus is on neighbourly relations between owners of plots on both sides. This uncomfortable proximity of enemies allows us to see boundaries as more than markers of separation. For sure, Sicilian boundaries imprint a history of violence on the landscape and divide people along categorical lines. However, they also reflect histories of inheritance and kinship, while providing points of contact and an unexpected moral order of neighbourhood relations. A focus on borders shared between plots managed by ‘antagonistic’ social groups exposes emergent relations of conflict and solidarity between their owners. Land boundaries can be markers of proximity and difference between opposed groups who find themselves owning plots next to each other. The boundary underpinning such divisions can make neighbours of feuding groups, rather than confining them to closed clusters.