This is a study in the historical geography of a medieval Norwegian province, based on field evidence, Danish and Norwegian, medieval and early modern sources, and 17th-to-18th century, Swedish cadastral maps. In previous literature, eastern Norway, including Bohuslän, is described as having been characterised by single farms with fields held in severalty. This study shows, however, that concentrated settlements, as well as subdivided fields existed in Bohuslän already in medieval times. The settlement development in Bohuslän, and possibly also in the rest of eastern Norway, must thus be seen as part of general European process, rather than a specifically Norwegian development, isolated from the rest of northern Europe. The specific forms that open fields took can, however be explained by some region-specific factors, among which the rules of inheritance were the most important.