Paired-associate stimuli are an important tool in learning and memory research. In cognitive psychology, many studies use materials for which the participants are expected to have little to zero prior knowledge (e.g., Swahili-English word pairs). Despite their theoretical usefulness, conclusions from these studies are difficult to generalize to real world learning contexts, where learners can be expected to have varying degrees of prior knowledge. Here, we tested prior knowledge for 111 country outline- name pairs for 287 participants, and we provide a database containing accuracy and response time distributions for each item. Prior knowledge ranged from near perfect to zero, thereby allowing researchers to select materials for which participants can be expected to have any desired degree of prior knowledge. As such, this database may provide a useful tool for research into learning in real world contexts where learners have (partial) prior knowledge.