Regional Studies. The days of vertical integration are over. Product development, manufacturing and other activities once done by single firms are now fields of collaboration. This raises questions about the spatial aspects of interfirm collaboration. Firms have partners in their direct environment, at a distance or in between, which means that traditional views on regional economic development no longer apply. It also means that a local-global dichotomy does not adequately describe today's economic landscape. This paper distinguishes four spatial scales - local, regional, nationaland international - and explores the distribution of interfirm collaboration across them, while taking project development over time into account.