The blockchain comes with the promise of being a disruptive technology with the potential for novel ways of interaction in a wide range of applications. Although scholarly interest in the technology is growing, a broad analysis of blockchain applications from a governance perspective lacks to date. This research pays special attention to the governance of blockchain systems and illustrates core governance decisions on 15 blockchain systems from four application domains. Based on academic literature, semi-structured interviews with representatives from those companies, and content analysis of grey literature, different blockchain governance decisions have been derived and their enactment described. The identification of them enriches the scarce body of knowledge on blockchain systems with a better understanding of how key governance decisions are enacted in practice.