This article examines the power and purpose of union peak bodies, focussing on one particularly powerful organisation, the Barrier Industrial Council in Broken Hill. We argue that the power and purpose of all such bodies is multi-dimensional, historically contingent and spatially specific. The most illuminating studies conceptualise peak bodies as agents of mobilisation, with power delegated by affiliates, and of economic and political exchange, with power derived from a ‘structural coupling’ with the state and capital. However, there is a third possible peak body purpose: social regulation and, specifically, the regulation of labour and commodity markets. This was a conspicuous activity of the Barrier Industrial Council, underpinned by success in mobilisation and exchange and by ‘place consciousness’. Understanding the variety of potential power sources holds the key to explaining not only why some peak bodies command more power than others but also why there is so much variation in peak union focus and behaviour.