In a survey of students from junior high through the undergraduate college level, males consistently out-performed females on a test covering map skills and physical, human, and regional aspects of geography. The gender gap was consistent across all four subfields. It widened with increased education and was significant even after accounting for numerous personal information items that might have explained the difference. This consistent performance difference involving the broad spectrum of geographic knowledge argues against explaining the gender gap as symptomatic of differences in a single underlying factor such as map skills or spatial abilities. Knowledge-based and nonknowledge-based explanations for the gender difference are discussed.