Mental models of the physical world can have profound impacts on how people view the Earth and Earth processes. In this study, undergraduate students (n=39) were interviewed and in-service science educators (n=110) completed questionnaires in order to examine and identify alternative conceptions about plate tectonics. Both interview protocol and questionnaires targeted conceptions about the spatial location of tectonic plates and the geographic locations of physical features and naturally occurring phenomena. Interviewees were recruited from multiple sections of introductory geology at a mid-western university. Interviews followed a semi-structured interview protocol to ensure consistency in questioning. During interviews, students were asked to express ideas verbally and diagrammatically allowing for the collection of artifacts, including drawings of Earth’s shallow interior and student generated maps. In-service science educators were recruited from across the United States using multiple National Science Teacher’s Association (NSTA) list-servers. Short, open-ended questionnaires about plate tectonics were distributed to the in-service population via e-mail. Alternative conceptions held by the study populations were determined by comparing interview (verbal and diagrammatic) and questionnaire (verbal) responses to scientifically acceptable explanations. Geographic locations of earthquakes, volcanoes, and mountains were collected from student maps and digitized in ArcMap for analysis. Using collected data, ‘student’ point patterns were created and compared to observed locations of earthquakes. Categorization of drawings (undergraduate) and responses (educators) indicates that the majority of undergraduate students (67%) and one-third (33%) of in-service educators do not recognize that tectonic plates are at the surface of the Earth. Using a chi-squared test of independence, placement of tectonic plates was also found to be dependent upon gender in both populations.