This paper presents the design, implementation and assessment of the Columbia River Basin Environmental Research Project (CERP) curriculum. CERP is an online inquiry-based, regional geographic curriculum designed to improve technology skills and content knowledge about water quality and watershed-level processes. Student attitudes and knowledge gains were assessed over a three-year period in a freshmen level general education inquiry class using pre- and post-surveys and work sample analysis. Results show students gained content knowledge, and Internet research and graphing skills. Our findings suggest that the CERP curriculum is effective in improving student understanding of complex environmental issues.