This plant occurs on buttes and badlands in the Powder River Basin and surrounding areas. The habitat is generally mixed-grass prairie on limestone, sandstone, shale, or siltstone.Astragalus barrii. Center for Plant Conservation. It grows alongside other species of Astragalus including A. gilviflorus, A. hyalinus, A. bisulcatus, A. racemosus, and A. spatulatus, and it must be in flower to be distinguished from other species with three leaflets on each leaf.
