This study explores students' conceptual thinking by examining the extent and complexity of their concept identification and organization in geography. The study investigated students' conceptual thinking through identification of salient geography concepts and construction of individual concept maps at three academic achievement and grade levels. The study involved 66 geography students from the 6th-, 9th-, and 12th-grade. Results from the study indicate students' conceptual thinking in geography is reflected in their achievement and grade levels. Other variables may be important contributors to students' conceptual thinking but those were not investigated. ANOVA results indicate not only increased conceptual understanding with increased achievement and grade levels, but also with increased performance on background knowledge, concept identification, and concept map construction instruments. Correlations among knowledge questions, number of concepts, and concept mapping scores also were statistically significant. In addition, attitude towards geography was statistically significant for achievement and grade; travel experience was statistically significant for achievement. (EH)