Site report on the 1986 excavations at Keinsmerbrug. This publication is part of the Odyssee project "Unlocking Noord-Holland's Late Neolithic Treasure Chest". The project Unlocking Noord-Holland's Late Neolithic Treasure Chest was initiated by Hans Peeters (then Dutch Cultural Heritage Agency, now University of Groningen) and received a grant by the Dutch Research Foundation NWO. On the basis of this grant and subsidiary grants from the universities of Leiden and Groningen and the unpaid involvement of various specialists from the Cultural Heritage Agency a multidisciplinary project on the Single Grave Culture of Noord-Holland saw its official start in September 2009. The project combines the research expertise from researchers from the Cultural Heritage Agency, two universities and various firms. This project aims to unlock and integrate cultural/ecological information and research data in order to provide a sound basis for cultural modeling and development of heritage management strategies. We will thereby obtain a better understanding of site variability in relation to landscape use, subsistence strategies and the material world of the inhabitants. It provides an opportunity to study a micro-region within the wider SGC culture, so far largely known from its burial context. Its place in relation to the communities in the central and eastern parts of the Netherlands can be assessed and possible long-distance contacts with related Corded Ware groups elsewhere can be studied, addressing the debate on the apparent uniformity of the Corded Ware Complex. These aims will be met by publishing three monographs on selected key sites: Keinsmerbrug, Zeewijk and Mienakker. All sites are characterized by their good preservation and wide variety in find categories available for detailed analysis. On the basis of these three site publications intersite analysis will be undertaken to address the key issues mentioned above. This archive is the result of the first of these three sites, Keinsmerbrug