Eriogonum codium is a species of wild buckwheat known by the common names basalt desert buckwheat and Umtanum Desert wild buckwheat. It is endemic to Washington in the United States, where it is known only from Hanford Reach National Monument in Benton County. It was discovered in 1995 during an inventory of the biodiversity of the monument and described to science in 1997. This species is a candidate for federal protection.