Allium dictuon is a species of wild onion known by the common name Blue Mountain onion. It is native to a small section of the Blue Mountains straddling the border between southeastern Washington and norhteastern Oregon in the United States. It grows in Columbia, Garfield and Walla Walla Counties in Washington, plus Umatilla and Wallowa Counties in Oregon. Allium dictuon grows in dry, open, rocky habitat. The vegetation in the area is dominated by bluebunch wheatgrass (Pseudoroegneria spicata ssp. spicata). The total population has been estimated to be between 200 and 500 individuals.