This paper reports the results of an archaeological survey and test excavation conducted in one of the ancient megalithic stele sites in south Ethiopia, Sakaro Sodo. The Sakaro Sodo stele site is situated in Gedeo zone, which is known to have the largest number and highest concentration of megalithic stele monuments in Africa, with an estimate of more than 10,000 stelae in sixty or more sites. Prior to our work, only one absolute date was available (850 ± 40 BP) (Joussaume 2012) from a stele site in the Gedeo zone, suggesting stele sites began to be constructed in the region approximately a millennium ago. We report here new AMS dates suggesting that stelae were being emplaced about 2000 BP, pushing the creation of these monuments back at least a millennium. Additionally, we report preliminary findings from characterizing the geochemical properties of obsidian artifacts recovered from stele sites, and stone used to make stelae. While compositional analysis of obsidian suggests long-distance movement of material from sources located in northern Kenya, petrographic microscopy and electron microprobe analyses show a strong connection of stelae to local geological tuff exposures/sources.