Borre in Norway is famous for its Late Nordic Iron and Viking Age (AD 400–1050) monumental burial mounds. Recently, ground-penetrating radar (GPR) surveys have revealed three large structures close to the mound cemetery. Their unusual layout and size, and location within such a prominent burial site, suggest that they were halls—high-status buildings mentioned in the Nordic sagas. The authors present the GPR results, discuss the buildings’ typological classification and provide a preliminary chronological framework. The latter suggests that the buildings coexisted with some of the burial mounds, and raises important questions about the significance of such buildings in Nordic mound-building societies.

The use of large-scale, high-resolution ground-penetrating radar surveys has increasingly become a part of Norwegian cultural heritage management as a complementary method to trial trenching surveys to detect and delineate archaeological sites. The aim of this article is to collect, interpret and compare large-scale, high-resolution ground-penetrating radar (GPR) survey data with results from trial trenching and subsequent large-scale excavations, and to extract descriptive and spatial statistics on detection rates and precision for both evaluation methods. This, in turn, is used to assess the advantages and disadvantages of both conventional, intrusive methods and large-scale GPR surveys. Neither method proved to be flawless, and while the trial trenching had a better overall detection rate, organic and charcoal rich features were nearly just as easily detected by both methods. Similarly, the spatial representability was similar, even though the total detection rates were lower with the GPR. This can be used as an argument in advance of integrating full-coverage GPR results into a site evaluation scheme, preferably in combination with other methods. Overall, these analyses have highlighted drawbacks and possibilities in both methods that are important contributions in understanding how to use them and integrate them in future site evaluations.

The Late Nordic Iron Age (AD 550–1050) was characterised by significant change in political, military, judicial and religious structures across Scandinavia, most clearly manifested in the appearance of high-status ‘central places’ in the landscape. Recent ground-penetrating radar surveys at Gjellestad in Norway have revealed a site comprising several large burial mounds—one of which contains a ship burial—in addition to a possible cult house and a feasting hall. This combination of features suggests that Gjellestad was part of a hitherto unknown central place on the eastern shores of the Oslofjord. If correct, the authors’ interpretations demonstrate that the layouts of these sites were formulaic, and that central places may be more common than previously thought.