XRF analysis of more than 1,300 pieces of obsidian from Wolf Village (42UT273) in the Utah Valley, Utah, shows that the obsidian originated from areas as far north as Bear Gulch, Idaho and as far south as the Mineral Mountains in southern Utah. Most of the obsidian, however, came from two Utah sources: Black Rock and the Topaz Mountains. The presence or absence of cortex, and the shape of pieces with cortex, shows that procurement was different for the two sources. Cortex on Topaz Mountain artifacts is much more common than on artifacts from Black Rock. Many flakes from Topaz also were strongly curved, while most pieces of Black Rock obsidian debitage were flat. This shows that Topaz Mountain obsidian was brought to Wolf Village as small nodules, while Black Rock obsidian came to the site in the form of large flakes or bifaces. We hypothesize that Topaz Mountain obsidian was likely picked up as small nodules by Wolf Village residents, possibly while hunting antelope or small game in the west desert south of Vernon, Utah. Black Rock obsidian, in contrast, may have been obtained through exchange with people living to the south.