The aims of this study were to examine spatial variation in the risk of union dissolution (divorce or separation) and to investigate the causes of this variation. Although there is an increased interest in variations in divorce and separation across countries, surprisingly, few studies have examined the spatial variation in the levels of union disruption within countries. Using rich retrospective survey data from Austria, we examined the relative contributions of demographic and socio-economic characteristics, selective migrations, and contextual factors to spatial variation in the risk of union dissolution. Our study showed, first, that union dissolution levels varied significantly across counties, as expected. Second, geographical differences in the type of union (cohabitation or marriage) accounted for some spatial variation in the risk of separation. Third, the socio-economic characteristics of couples and selective migrations did not explain any of the spatial variations in the union dissolution levels. Fourth, a significant spatial variation in separation and divorce after controlling for compositional factors suggested that there were also contextual factors. We examined the role of various contextual characteristics for explaining spatial variation in divorce and separation, including the level of urbanisation, economic well-being of an area, and characteristics measuring the cultural-normative climate of a region. Copyright © 2011 John Wiley & Sons, Ltd.