It is a truism that environmental management has experienced a significant change in the locus of governing, in which centralised forms of steering have been gradually replaced by more collaborative management approaches organised at the ecosystem scale. Whereas much research capital has been expended on informing their design and promoting their uptake, surprisingly little systematic comparative empirical research exists on the precise nature and extent of what is often described as a 'paradigm shift' in governing. We address this gap by examining how one issue often deemed to require deeper 'collaboration', namely, catchment management, has been addressed in three comparable federal political systems: the European Union; the USA; and Australia. On the basis of a fresh and more comparable account of the forms and modalities of collaboration, we reveal that, although collaboration has undoubtedly grown in recent decades, its depth and extent remains highly variable both across and within the three cases. We also examine what these subtly different geographical 'contours of collaboration' imply for future research and practice. [ABSTRACT FROM AUTHOR]