Small communist strongholds were commonly nicknamed "Little Moscow", both in Britain and in Europe. Small-place communism has been widespread since the interwar period, often in distinctly hostile surroundings. In this article, based on research into a number of cases in western Europe, I try to identify common characteristics which might explain their receptiveness to communist policies and ideas. My aim is to present a taxonomy for further research. Most of the places that I researched were isolated, recently developed, and mono-industrial. They were populated by a wave of migrants who had formed mono-occupational, pioneer societies. Second-generation migrants turned to communism and built "occupational communities" based on trade unions and other associational activities. Often they continued militant traditions of earlier socialism, anarchism, or syndicalism; others had a tradition of irreligiousness or religious indifference.