As elsewhere in the United States, in Montana the Great Depression of the 1930s was followed by the spending programs of the New Deal. The works projects had a great impact on the state. Not only did programs like the Civilian Conservation Corps (CCC) and the Works Progress Administration (WPA) give employment and training to people who were out of jobs, but they produced monumental results. One of the largest public works projects in the country was Fort Peck Dam, completed in 1940 to dam the Missouri. Going-to-the-Sun Highway in Glacier Park was a CCC project. Dozens of roads, parks, fairgrounds, and other landmarks of public infrastructure were also built.

After the end of the New Deal era, government spending in Montana ceased to be a civilian affair and was given over to the military. Malmstrom Air Force Base was built in Great Falls in 1942 as a transit base for war materials shipped to the United States’ then-ally the Soviet Union. By the 1950s it became a strategic air base that was assigned fighter jets to defend against the then-enemy Soviet Union. In the 1960s Malmstrom became the first center for the Minuteman missile system. Two hundred Minuteman missiles were buried in silos under 23,000 acres of central Montana prairie by 1970,, pointed at equivalent missiles in Russia. Glasgow Air Force Base brought population and business to that eastern Montana town until the base was closed in 1969.