Barrels, as packaging for a range of traded goods, often ended up re-used in wells and latrines in towns. Tree-ring analysis of barrel finds not only supplies us with a precise chronology for their manufacture, and for the dating of the contexts in which they are found. The region of origin of the wood, through provenance determination, reveals connections between regions that might not necessarily be detected in the other finds from a site. In this talk, I will present some of the most recent provenance determination results that have emerged through my research in Northern Europe.