Geography possesses the capability to integrate diverse disciplinary perspectives and equip students with the ability to develop powerful knowledge-based skills, which are increasingly crucial for addressing complex global challenges. Consequently, research on the study of powerful knowledge in geography focuses on examining how to cultivate students' capabilities to impact society. This study aims to research how tasks in geography textbooks for upper secondary education support the development of powerful knowledge in geography. Powerful knowledge in geography refers to students' competencies that enable them to influence society. Three geography textbook series for upper secondary education, developed based on the Finnish National Core Curriculum for Basic Education in 2014, were analyzed in this research. The tasks in the textbook series were categorized and further analyzed thematically and statistically. The findings suggest that tasks in upper secondary geography textbooks to some extent facilitate the development of students' powerful knowledge, but the tasks are not evenly distributed among the different types of powerful knowledge. Certain types of powerful knowledge in geography are emphasized more than others in the tasks. The tasks in geography textbooks broadly support the acquisition of general geographical facts and the understanding of geographical phenomena through cause-and-effect relationships. However, there are fewer tasks that develop students' competencies to comprehend the production of knowledge, impact society, and transform their worldview. While the tasks in the different textbook series are similar in the context of powerful knowledge in geography, some differences exist. The eOpin geography textbook series stands out from the others because there are relatively fewer tasks that address cause-and-effect relationships, compared to the Otava and Sanoma Pro geography textbook series. Conversely, the eOpin textbook series contains more tasks that promote the acquisition of basic geographical facts, while the Otava textbook series has more tasks that provide knowledge to understand the production of knowledge. The Sanoma Pro textbook series, on the other hand, contains the most tasks that increase students' competencies to influence society. Further research of powerful knowledge in geography at the upper secondary level is essential, as the topic has been under-researched. The accumulation of powerful knowledge in students alone does not cause a change in students' social influence, as change must stem from individuals' values, attitudes, and identities, whose relationship to powerful knowledge should be studied.