This article evaluates two of the most productive recent areas of research in the historical geographies of solidarity: first, work relating to class and the labour movement; and second, debates clustered around race and colonialism. The two are, of course, not entirely distinct, and there has been much useful thinking at their intersections. I suggest that questions of mobility have been crucial in thinking about the formation of diverse solidarities across geographical and social boundaries. The article looks at how relationships can both be developed across differences of gender, race, and sexuality and how solidarities can be used to entrench forms of oppression and inequities of power. Thinking about this issue through the concept of intersectionality, I argue, would be a useful way of engaging with such questions. I suggest three areas which could be developed further. First, there is potential for a greater engagement with theoretical debates around the nature of solidarity itself. Second, historical geographers could pay more attention to the role of memory and “usable pasts.” Finally, I argue that more ambitious historical narratives, framed within wider social processes, would allow us to make broader arguments about how solidarity develops over time.