The local level is highly important for political engagement, as political issues that are relevant to citizens' daily lives are discussed at this level. Therefore, political parties are especially interested in organizing a strong local basis. Yet, empirical research on the local party units is rather scarce, particularly with respect to their social media activities. We do not know whether the local units of political parties are nowadays active players in the most important communication sphere, and nor do we know anything about potential driving forces of their activities on social media. Using big data, we are able to demonstrate that local party units in Germany are especially active on Facebook during a heated election campaign. Interestingly, we also confirm this observation with regard to user activities. Furthermore, our results reveal that the local basis of the German right‐wing populist party Alternative for Germany has an insurmountable lead on Facebook—in terms of both published posts and user response. This finding supports the thesis that a right‐wing ecosystem on Facebook has been established in Germany. Besides election and party effects, we find that urbanized areas provide better opportunities for the social media usage of political parties and citizens.