Obsidian has been noted at archaeological sites in the Midwest for over 160 years, although very few artifacts made from this material are recorded in archaeological contexts in Missouri. Background research revealed that only 16 obsidian artifacts from 13 sites had been documented from the state and that only 5 of the specimens had been geochemically analyzed and attributed to a source. Recent excavations at the Droste site (23PI1291), a Late Woodland period site in northeast Missouri, yielded two obsidian artifacts. The two specimens from the Droste site along with two previously unsourced obsidian artifacts from the Burkemper site (23LN104) and two from the Stapleton site (23HD110) were tested for trace element composition via X-ray fluorescence analysis. This article reports the results of these geochemical analyses, reviews the other obsidian artifacts reported from Missouri, and examines the cultural context and source of obsidian artifacts from other states in the upper Midwest.