This chapter explores the origins and evolution of the industry cluster concept with a focus on the efforts undertaken in the United States. It presents the different scholarly perspectives on the concept of agglomeration and provides details of the specific U.S.-based initiatives on developing and using the benchmark industry clusters for regional economic development purposes. In addition, variants such as knowledge-based and integrated industry clusters are discussed, including the data limitations. The chapter concludes with a summary and briefly describes new avenues of research on agglomeration, competitiveness, and clusters.