Shrubs, dioecious or less commonly monoecious, mainly 10-25(-35) dm, as broad or broader, unarmed or rarely so; branchlets terete, commonly puberulent. Leaves persistent, alternate, petiolate; blade gray-green, deltate to rhombic, ovate, or oblong-elliptic, 5-50 × 5-50 mm, base truncate to subhastate, margin entire to repand or subhastately lobed, apex rounded to obtuse, scurfy. Staminate flowers yellow, in clusters 1-2 mm wide, borne in panicles 0.5-5 dm. Pistillate flowers with less complex panicles. Fruiting bracteoles sessile, orbiculate to oval, greatly compressed, mainly 3-4.5 mm and wide, crenulate, apex rounded. Seeds brown, 0.8-1.6 mm wide. 2n = 18.
Flowering spring-fall. Saline to essentially non-saline drainages, stream and canal banks, roadsides, warm desert shrub, saltbush, and riparian communities; 70-1000 m; Ariz., Calif., Nev., Utah; Mexico.
Materials of big saltbush from the coastal and near coastal regions of California have somewhat broader, merely ovate, rounded leaves, and they have been regarded either at species level as Atriplex breweri S. Watson or at either varietal or subspecific level (see synonymy). The plants intergrade completely in interior situations with typical A. lentiformis, and their recognition at taxonomic level seems superfluous. C. A. Hanson (1962) noted the existence of putative hybrids between A. lentiformis and the herbaceous species A. leucophylla and A. davidsonii. Putative hybrids are also known between this species and A. canescens.