Astragalus trichopodus is a species of legume known by the common name Santa Barbara milk vetch. It is native to southern California and Baja California, where it grows in several types of open habitat. This is a robust perennial herb producing a branching stem up to about a meter in maximum height. The hairy stem is lined with many leaves each up to 20 centimeters long which are made up of several pairs of widely-spaced lance-shaped leaflets each up to 2.5 centimeters in length. The flower cluster is a raceme of up to 50 flowers which are cream colored and sometimes tinted with light purple. Each flower is 2 or 3 centimeters long including its tubular base of sepals. The fruit is a laterally compressed, slightly inflated legume pod up to 4 or 5 centimeters long which dries to a papery texture. The fruits hang in bunches where they develop from the flower cluster. Each pod contains many seeds.