The Targhee is named after the Targhee National Forest, which surrounds the U.S. Sheep Experiment Station in Idaho. Their ancestors were Rambouillet, Corriedale, and Lincoln sheep.
Development of this breed for the Western ranges of the U.S. began as early as 1900. The flock book was closed in 1966, meaning that only the offspring of registered Targhees could be registered).