Recommended concentrations for 38 elements in the U.S. Geological Survey reference sample, Ohio Shale (Devonian) SDO‐1, are presented here. For an additional 25 elements, average concentrations or ranges are reported for information. Also presented are the supporting analytical data and a description of the statistical procedure used in deriving recommended concentrations from that data. The sample is a brownish‐black, fissile, platy shale containing flattened pyrite nodules and a high organic content. It is typical of “eastern gas shale”, in contrast to the USGS reference sample SGR‐1, which typifies oil shale from the Green River Formation. SDO‐1 was collected from the Huron Member of the Late Devonian Ohio Shale in western Rowan County, Kentucky. The sample is available as fine splits for detailed chemical analysis and as coarse splits for hand, microscopic, and microfossil