This article offers a way to measure agreement in participatory mapping. We asked subject matter experts (SMEs) to draw where Sudanese ethnic groups were located on a map. We then used an eigenanalysis approach to determine whether SMEs agreed on the location of ethnic groups. We used minimum residual factor analysis to assess the extent of interinformant agreement among SMEs' judgments of four ethnic groups' spatial locations. Although we found little evidence of the lumper/splitter problem, some SMEs drew larger polygons than others, and we provide directions on how to reduce this potential bias. Finally, the results of the geospatial agreement analysis were validated through a comparison of other sources of geospatial data for three of the four ethnic groups.