We describe the development of climate vulnerability maps for three Sahelian countries – Mali, Burkina Faso, and Niger – and for coastal West Africa, with a focus on the way the maps were designed to meet decision‐making needs and their ultimate influence and use in policy contexts. The paper provides a review of the literature on indicators and maps in the science–policy interface. We then assess the credibility, salience, and legitimacy of the maps as tools for decision‐making. Results suggest that vulnerability maps are a useful boundary object for generating discussions among stakeholders with different objectives and technical backgrounds, and that they can provide useful input for targeting development assistance. We conclude with a discussion of the power of maps to capture policy‐maker attention, and how this increases the onus on map developers to communicate clearly uncertainties and limitations. The assessment of policy uptake in this paper is admittedly subjective; the article includes a discussion of ways to conduct more objective and rigorous assessments of policy impact so as to better evaluate the value and use of vulnerability mapping in decision‐making processes.