Eriogonum diatomaceum is a species of wild buckwheat known by the common name Churchill Narrows buckwheat. It is endemic to Nevada in the United States, where it is known only from the Pine Nut Mountains in Lyon County. It is limited to the Churchill Narrows near Fort Churchill State Historic Park. This plant was discovered in 1997 and described to science in 2002. There is only a single population of the plant, split into about 15 occurrences and containing a total of less than 50,000 individuals. All the plants are within about three square miles of Bureau of Land Management lands.