Pennsylvania supplied 31% of American steel during World War II and 20% of steel worldwide.

The National Munitions Company was based in Eldred, Pennsylvania and was initially founded in 1941 for the purpose of producing arms for the British military. It soon began producing arms for the American military in December of 1941. Around 1,500 people worked there and 95% of them were women. 

Pennsylvania had over forty military bases during World War II although they ranged in scope and competence.

The Sun Shipbuilding Company in Chester, Pennsylvania created almost 40% of the tanks used by the U.S. in World War II. 

The American Bantam Car Company in Butler, Pennsylvania created the first Jeeps but also manufactured weapons for the American military come 1943.