Obsidian and ceramic artifacts from the Otumba project were analyzed by instrumental neutron-activation analysis. Sources for the obsidian were determined by comparison to a databank of Central Mexican source analyses. Ceramic sources were determined by comparison to a series of reference groups from the Basin of Mexico and by comparison with raw material samples. Obsidian from the lapidary workshop (Operation 11) comes predominantly from the Otumba and Pachuca sources. There is also an unknown compositional profile present among the artifacts. This profile may derive from a not-yet-sampled flow within one of several nearby obsidian-source areas, such as Otumba or Paredon. The majority of Otumba ceramics fall into a large group derived from clays of the Teotihuacan-valley alluvium. Aztec II Black-on-Orange and red-ware samples come from other sources in the eastern basin. Ceramics from sites along the trade route leading northeast toward Tulancingo include figurines derived from Otumba, figurines probably made locally near Tepeapulco and Tulancingo, and long-handle censers probably made in the latter two locations.