Summary Entrepreneurship and new firm creation are critical for regional and national economic growth. In times of crisis and decline, we often turn to entrepreneurship as the starting point for growth. Cities, regions, and nations formulate policies aimed at stimulating entrepreneurship. But where does entrepreneurship come from? And how can we explain and promote rapid regional shifts in entrepreneurial activities? These are the core questions in this monograph. Based on new academic research on entrepreneurial ecosystems, this monograph uses one of the most comprehensive datasets covering more than 500,000 startups in Denmark over more than 30 years with the aim of vastly increasing our understanding of local entrepreneurial processes with deep new insights for academics and stakeholders.