The Chicago blues is a form of blues music indigenous to Chicago, Illinois. Chicago blues is a type of urban blues. Urban blues evolved from classic blues following the Great Migration, or the Great Northern Drive, which was both forced and voluntary at times, of African-Americans from the southern United States to the industrial cities of the north, such as Chicago. Muddy Waters directly joined that migration, like many others, such as in Florida, avoiding the more harshly southern Jim Crow laws.
Bruce Iglauer, founder of Alligator Records stated that, "Chicago blues is the music of the industrial city, and has an industrial sense about it." Additionally, recognizing the shift in blues, Chicago Blues singer and guitarist, Kevin Moore expressed the blues transition stating, "You have to put some new life into it, new blood, new perspectives. You can't keep talking about mules, workin' on the levee." Chicago blues was heavily influenced by Mississippi bluesman who traveled to Chicago in the early 1940s. The development of blues, up to Chicago blues, is arguably as follows: Country blues, to city blues, to urban blues". Chicago blues is based around the sound of the electric guitar and the harmonica, with the harmonica played through a PA system or guitar amplifier.
When America became embroiled in World War II, it served to increase the exodus of African-Americans from the Southern states northward to cities like St. Louis, Detroit and Chicago. Former sharecroppers were moving out of the rural areas of Mississippi, Alabama, and Georgia to find jobs in the growing industrial sector and provide better opportunities for their families. Along with the many agricultural workers who came to Chicago in search of jobs, there were a number of blues musicians that made the trip as well. Arriving in Chicago, they began mixing with the first generation of immigrants, taking on an urban sophistication in place of their rural roots.