Michael Cassius McDonald

Michael Cassius McDonald (c. 1839 – August 9, 1907) was a crime boss, political boss, and businessman based out of Chicago. He is considered to have introduced organized crime to the city, and to have also established its first political machine. At the height of his power, he had influence over politicians of all levels in the state of Illinois.

McDonald permanently settled in Chicago as an adult sometime after the American Civil War. McDonald ran gambling parlors in the city. As a crime boss, he developed a system in which he would guarantee the city's gambling dens and brothels protection from interference in exchange for payment. A Democrat, McDonald was involved in the city's politics, and, at his peak, wielded massive influence over it. McDonald was also involved in numerous business ventures. He was one of the principal figures behind the Lake Street Elevated Railroad Company, which built the Lake Street Elevated rapid transit line in Chicago.

In the mid-1890s, McDonald retired from the gambling business, and his gambling circuit deconsolidated under the leadership of several different crime bosses.