The report traces the locations of manufacturing industries that are significant suppliers to the set of manufacturing industries that fulfill procurement orders from the U.S. Department of Defense. These industries, and the counties that house them, may be strongly linked to national defense activities even though the relationship is indirect, through the firms that purchase their products. Much more so than the industries that serve defense contracts directly, these industries that are “upstream” along the manufacturing supply chain are concentrated in the Great Lakes region, along with major metropolitan areas throughout the country. Counties that meet both size and local dependency criteria with respect to these supplier industries are located in large groupings in Indiana, Michigan, Ohio, and Wisconsin, and a smattering of such counties are found as isolated standouts in several other states.