Twenty-mule teams were teams of eighteen mules and two horses attached to large wagons that transported borax out of Death Valley from 1883 to 1889. They traveled from mines across the Mojave Desert to the nearest railroad spur, 165 miles (266 km) away in Mojave. The routes were from the Harmony and Amargosa Borax Works to Daggett, California, and later Mojave, California. After Harmony and Amargosa shut down in 1888, the mule team's route was moved to the mines at Borate, 3 miles (5 km) east of Calico, back to Daggett. There they worked from 1891 until 1898 when they were replaced by the Borate and Daggett Railroad.

The wagons were among the largest ever pulled by draft animals, designed to carry 10 short tons (9 metric tons) of borax ore at a time.