  In this online appendix we provide additional information and analyses to
support "The Determinants of Social Connectedness in Europe." We include a
number of case studies illustrating how language, history, and other factors
have shaped European social networks. We also look at the effects of social
connectedness. Our results provide empirical support for theoretical models
that suggest social networks play an important role in individuals' travel
decisions. We study variation in the degree of connectedness of regions to
other European countries, finding a negative correlation between Euroscepticism
and greater levels of international connection.
