Eriogonum butterworthianum is a rare species of wild buckwheat known by the common name Butterworth's buckwheat. It is endemic to the Santa Lucia Mountains of central Monterey County, California, where it is known from a few occurrences in the wilderness southeast of Big Sur in the vicinity of Junipero Serra Peak. It grows in woodland and chaparral habitat on sandstone soils. This is a small clumpy shrub or subshrub growing up to about 30 centimeters tall and wide. The reddish-green, woolly leaves are oval in shape and curled under at the edges. They are up to 2 centimeters long. The inflorescence is a cluster of flowers up to 2 or 3 centimeters wide, each individual flower a few millimeters wide and dull yellowish to pinkish in color.