To better understand geographic trends in arsenic occurrence, researchers recently used an interactive visualization technique to link geospatially referenced arsenic concentration information from a water quality database with data contained in digital terrain elevation data (DTED) files. DTED files allow users to develop 3-D plots of arsenic concentration and topography. For example, the plots show high arsenic is 1) associated with topographic transition from plains to piedmont in New Jersey, 2) found in Oklahoma in a region of transition to lower elevation, and 3) apparent in the southeastern portion of California's Central Valley. These results are consistent with how arsenic moves in organic-rich sediments of river valleys. However, further statistical analysis is required to confirm the significance of this association.