Skip to main content

During World War II, the United States was known as the Arsenal of Democracy because of its great manufacturing capabilities. The title applied to the tens of thousands of workers who worked in Michigan’s auto plants making weapons of war.

In the years before World War II, Detroit factories made millions of cars, trucks, and buses making them a logical industry that the government would turn to for production in a time of crisis.

At first, auto manufacturers did not want to produce war goods. In 1940, with much of the world at war, President Roosevelt knew that the United States needed to improve the armaments of its armed forces. Roosevelt asked William Knudsen, president of the General Motors Corporation, to get the support of the auto industry.

By the time the United States entered the war in 1941, Knudsen convinced automakers to build tanks and planes. Automakers then stopped making cars and turned all their attention to war production.

Automakers made items they had never produced before. They redesigned weapons to make them easier to mass produce and to use in combat.

By the war’s end, the automobile industry produced a variety of war materiel: bombs, rifles, torpedoes, and ammunition. However, it was the complex machines that received the greatest recognition. This included four million engines, 2.6 million trucks, 50,000 tanks, and 27,000 airplanes.

To win World War II, Americans needed a great deal from the auto industry, and they got it.


In mid-1940, the government asked K.T. Keller, president of the Chrysler Corporation, if his company could make tanks. Keller responded, “Yes.” He then asked, “where can I see one?”

Within weeks, Chrysler and the U.S. government signed a contract. The government agreed to build a plant in present-day Warren, Michigan where Chrysler would make tanks. Chrysler named the new plant the Detroit Arsenal.

On April 24, 1941, the governor of Michigan and other guests gathered at the Detroit Arsenal for the dedication of the plant. The star of the day’s festivities was a 30-ton steel monster – the first tank delivered from the Arsenal. The M3 tank fired its guns and smashed through telephone poles and a small wooden house.

Soon, tanks were rolling off the assembly line. One year after the plant’s dedication, the Arsenal delivered its 2,000th tank. In July 1942, the Arsenal started making the M4 Sherman tank – one of the war’s best known armored vehicles.

In December 1942, the Arsenal’s 5,000 workers set an all-time monthly record by producing 907 Sherman tanks.

When World War II ended in August 1945, the Chrysler Corporation had built 22,234 tanks in the Detroit Arsenal.

In the years following World War II, tanks continued to be manufactured at the Detroit Arsenal. By the time tank production ended in the 1990s, the Detroit Arsenal built more than 60,000 tanks. Today, the Detroit Arsenal remains the home of the U.S Army Tank Automotive and Armaments Command.

Willow Run

One of the best-known war production achievements of World War II was the Ford Motor Company’s Willow Run bomber plant. Located near Ypsilanti, Willow Run was the idea of Henry Ford, who claimed that the Ford Motor Company could make 24 planes per day.

This was an unbelievable claim, but Ford’s reputation as a mass-production genius in building automobiles led the government to ask him to manufacture planes. The government agreed to construct a factory where Ford would build B-24 bombers along a one-mile-long assembly line. Construction of the plant began in April 1941.

Ford completed Willow Run in September 1942. It was the largest assembly plant ever built up to that time. It had an airport next to the factory so the new planes could fly away.

By the end of 1943, Willow Run produced bombers at a rate of one per hour. The total number of B-24s built at Willow Run was 8,685. The last bomber moved off the assembly line on June 24, 1945.

After the war, Willow Run changed to automobile production. It closed in 1995, but the Willow Run airport remains open.


Search the Digital Archive