Abstract: The research object of this study is the changes in the number of people belonging to the Russian-speaking diaspora in California. As the research subject, the author chose the social composition of migrants in the first pre-revolutionary wave of emigration to this region. The author also addresses the issue of the influence of the Russian colonization in the northwestern part of the American continent in the 18th-19th centuries on the process of forming a diaspora in California. Of particular importance to this study are the official statistics from the Immigration Commission and the United States Census Bureau. These sources are analyzed and compared with the findings presented in pre-revolutionary and modern Russian historiography. The methodological basis of this study and the provisions put forward in this work are the principle of historicism, the comparative historical method and the systematic approach. The author used materials from consular reports and official notes found in the collections of the Archive of Foreign Policy of the Russian Empire. The study's main findings are the thesis of the multi-ethnic nature of the California pre-revolutionary diaspora. The social composition and size of the community at each stage of its formation were also established.