Shaggy milk-vetch is a perennial wildflower with a cluster of incurved to erect stems from 3-25 cm long. The stems and leaves are covered with widely spreading to ascending hairs which measure from 1-2.5 mm long, giving the species its name of "shaggy" milk-vetch. The pinnately compound leaves are 4-15 cm long with 11-21 oblong-obovate, obovate -wedge-shaped or elliptic leaflets from 5-18 mm long.
The flower stems are erect or incurved-ascending and measure from 4-11 cm long. The racemes are 10-35 flowered and generally held above the leaves. The tubular calyx is 8.5-14 mm long and covered with long black or whitish hairs. The teeth of the calyx are narrowly awl-shaped and measure from 1.5-4 mm long. The corolla is reddish-purple in color with the moderately recurved banner measuring 15-21 mm long. The wings are 12-18 mm long while the keel is 12-16 mm long. The pod is 18-25 mm long and 4.5-6 mm wide and covered with long spreading hairs from 1.5-3 mm long. The pod is linear, oblong-elliptic or linear-lanceolate in shape and is shallowly arched to nearly half circular.
Shaggy milk-vetch may be found on sandy, rocky or clay flats, hillsides and ridges amongst low sagebrush or occasionally amongst juniper or pinyon pine between the elevations of 800-2100 meters.
Shaggy milk-vetch may be found from Lake County in south-central Oregon east through the Owyhee country of southeastern Oregon and southwestern Idaho. It is found southward along the eastern base of the Cascade and Sierra Nevada Mts. of northeastern California and into western Nevada where it is found southward to Esmeralda County.