The East Hills rise out of the Snake River Plain southeast of Declo, ID, in Cassia County. These are foothills to the neighboring Cotterell Mountains and Albion Mountains. This notion is confirmed by looking at the rocks. The East Hills contain Cotterell basalts as well as ancient Albion metamorphics. The high point of the East Hills the Declo Benchmark or East Hills HP. Of more recent note, the world’s largest potato-processing company was founded near Declo in 1923 by a young J.R. Simplot.