The Ford Motor Company had begun construction of the plant in April of 1941, and it was completed in early 1942. Industrial architect Albert Kahn designed Willow Run, one of the largest manufacturing plants under one roof in the world. It was a mile long and a quarter of a mile wide, cost $165 million and had 70 assembly lines.

Production of the B-24 Liberators began there in 1942, and 8,685 of them were built during the plant's operation. At its peak, the plant employed 42,000 men and women. Now, the Willow Run plant is the General Motors Hydra-matic Division, makers of automatic transmissions.